7. SECTION INTRODUCTION

Transcription

1 7. SECTION-5 Selection of efficient organic wastes in terms of plant straws, green leaves of botanicals and animal manures in the management of rootknot nematode, Meloidogyne incognita infecting chickpea var. Avrodhi 7.1 INTRODUCTION Root-knot nematodes are recognised as a serious and economically most important pest of a wide range of crops including vegetables and legumes around the world (Sikora and Fernandez, 25; Javed et al., 26, 28; Trifonova et al., 29). The most destructive species is Meloidogyne incognita which causes dramatic loss in a number of economically important agricultural and greenhouse crops. There are various control measures for the management of root-knot nematode such as chemical control, organic amendments, biological control and cultural practices (Randhawa et al., 21; Kim, 21; Rajendran and Saritha, 25; Akhtar and Malik, 2). In the recent past, several fumigants and nematicides have been withdrawn from the market due to environment and human health hazards (Rich et al., 24). Moreover, consumer demand for safe food has forced farmers to reduce the use of chemical pesticides. Among pesticides, nematicides are the most vulnerable because these are highly toxic to humans and its application resulting groundwater contamination, causing soil and water pollution, and some of them persist for long in crop residues (Sukul et al., 21; Tsay et al., 24; Oka, 21). Keeping these facts in view, researches all over the world get concentrated in standardizing the nematode management strategies by using non-chemical and ecofriendly approaches (Southey, 1986; Pinkerton et al., 2; Bakshi, 25; Padgham and Sikora, 27; Mashela et al., 28). One of the alternative method for the management of nematodes is the application of organic amendments in the soil (Khan et al., 1974; Alam et al., 1978; Mian and Rodriguez-Kabana, 1986; Agyarko and Asante, 25). This method has been used since the beginning of the agriculture. Organic amendments have consistently been shown to have beneficial effects on soil nutrients, soil physical conditions, soil biological activity and thereby improving the health of plants and reducing population of plant-parasitic nematodes (Addabbo, 8

2 1995; Oka et al., 2; Garcia-Alvarez et al., 24). Organic amendments used for nematode control are extremely heterogenous, including green manures (number of plant parts, by-products and residues), animal manures, animal beds (sawdust, straw), composts, soil urban residues, and a variety of agro-industrial by-products (Cook and Baker, 1983; Hoitink, 1988; Akhtar et al., 199; Akhtar and Mahmood, 1994; Addabbo, 1995; Oka et al., 27). The addition of many organic soil amendments particularly those with high nitrogen contents, may be effective alternative for the management of Meloidogyne spp. and other plant-parasitic nematodes (Khan et al., 1974; Alam et al., 1979; Boddey et al., 1997; Cakmak, 22). A number of organic additives including oil-seed cakes, chopped plant parts, seed-dressing with plant extracts, crop residues etc. have been used as nematode as well as fungal controlling agents (Akhtar and Alam, 1993; Siddiqui and Alam, 199; Nicolay et al., 199; Abawi and Widmer, 2; Tiyagi et al., 21; Mahmood et al., 25). An extensive literature on soil amendments has been described in the past (Singh and Sitaramaiah, 1973; Muller and Gooch, 1982; Addabbo, 1995). Addabbo (1995) summarized the research on organic amendments from As organic amendments differ in physical and chemical composition (Bulluck et al., 22a), their effects on soil properties and nematode communities may vary (Bulluck et al., 22b). Various mechanisms are involved in the nematicidal action of organic amendments (Stirling, 1991), some release compounds toxic to nematodes, like phenols, tannin, azadirachtin, ricinin (Mian and Rodriguez-Kabana, 1982; Rossner and Zebitz, 1987; Rich et al., 1989) or derived from the decomposition process in the soil, like ammonia, nitrites, hydrogen sulphide (Rodriguez-Kabana, 1986). Amendments may also provide a favourable substrate for the sustenance of soil micro-fauna and micro-flora (Linford, 1937; Linford et al., 1938) which can include direct predators (micro-arthropods) or parasites (fungi, bacteria) of nematodes, or which suppress soil nematode population indirectly through the production of enzymes (Rodriguez-Kabana et al., 1983; Galper et al., 199) or toxic metabolites, such as antibiotics of bacterial origin. The rate of decomposition of organic amendments influences supply of plant nutrients and plays a key role in structuring soil nematode communities (Ingham et al., 1985). Nitrate and ammoniacal nitrogen accumulated during decomposition are toxic to plan-parasitic nematodes (Mian and Rodriguez-Kabana, 1982). Rodriguez- 9

3 Kabana et al. (1987) reported that the nematicidal activities of an amendment depended on its chemical-composition and the type of organisms that develop during degradation. The nematode management potential of an organic soil amendment is directly related to N, C content and inversely related to C/N ratio (Mian and Roduguez-Kabana, 1982). During the past two decades, extensive work has been conducted on the utilization of plant-products in nematode management. Linford et al. (1938) were the first to observed the nematicidal effect of applying chopped pineapple leaves into the soil, infested with Meloidogyne spp. Amendments with plant materials on that crop and reduce population because they contain nitrogenous compounds, and other nemato-toxic chemicals, and affect the development of predators and parasites of nematodes. Plants straw also cause an increase in the plant growth and reduce the nematode population of M. incognita in tomato (Siddiqui and Mahmood, 23). Green manures of different plants/botanicals are reported to reduce the incidence of root-knot disease in various crops in field and greenhouse conditions (Akhtar, 1993; Akhtar and Malik, 2; Jourand et al., 24; Nazli et al., 28; Pakeerathan et al., 29). Considerable progress has been made in the utilization of organic materials as soil amendments for the control of plant-parasitic nematodes (Singh and Sitaramaiah, 197; Muller and Gooch, 1982; Akhtar and Alam, 199, 1993; Akhtar and Mahmood, 1993; Akhtar, 1997; Khan et al., 21; Kimenju et al., 24). Various kinds of organic and inorganic wastes have been shown to reduce nematodes population (Addabbo, 1995; Jonathan et al., 2; Khan et al., 21). The incorporation of organic material into the soil reduces root-knot densities (Muller and Gooch, 1982). Oil cakes, sawdust, urea and bagasse have been used with some success (Singh and Sitaramaiah, 197, 1973; Sikora et al., 1973). Haseeb et al. (1978) observed highest reduction in nematode population when soil was amended with chopped leaves of Calotropis procera. Muller and Gooch (1982) reduced nematode population and increased yield by applying organic amendments such as sawdust, compost, green manure and chicken manure. Akhtar and Alam (1984) showed that soil amendments (chopped flowers of different plants) brought about reduction in population of all genera of plant-parasitic nematodes. Haseeb et al. (1978) found that incorporation of chopped shoots of latex bearing plants significantly suppressed the population build 1

4 up of Rotylenchulus reniformis and Tylenchorhynchus brassicae and root-knot nematode. Akhtar and Alam (199) showed that agro-wastes of some harvested crops viz., marigold, mustard and sunflower showed highly significant inhibitory effect on development of root-knot nematodes and population of other plant-parasitic nematodes. Marigold plant residues were most effective followed by mustard and sunflower. In addition to their suppressive effects on nematode density, organic amendments improve soil structure and water holding capacity but large quantity is needed (Mc Sorley and Gallaher, 1995). Plants of the family asteraceae and cruciferae are receiving increased attention as novel tools for the management of plant-parasitic nematodes (Daulton and Curtis, 1963; Suatmadji, 1969; Khan et al., 1971; Mojtahedi et al., 1991; Mc Sorley and Frederick, 1995; Perez et al., 23; Monfort et al., 27). Research on the utilization of waste materials such as oilcakes, chitin, compost, animal and plant by-products, livestock, poultry and green manures appear promising for reducing population of plant-parasitic nematodes (Akhtar et al., 199; Akhtar and Alam, 199, 1992, 1993; Akhtar and Mahmod, 1994, 1995, 1996). Application of animal by-products are also used in crop management systems that aim to reduce or eliminate synthetic inputs (Mian and Rodriguez-Kabana, 1982; Abawi and Widmer, 2; Mc Sorley and Frederick, 1999). Compost and animal manures are of major importance in providing fertility in organic farming systems, since synthetic fertilizers are prohibited (Lampkin, 199; Stockdale et al., 21) and in suppresing nematode population (Everts et al., 26). Composts based on cattle manure were suppressive to M. javanica in pot and in-vitro experiments. Chemical analysis of the composts and leachates from the soils suggested that high electrical conductivity (EC) values and high concentrations of nitrogen, especially, N- NH 3 /NH + 4 rather than N-NO 3, suppressed the nematodes. Chicken litter was also found to reduce the number of M. arenaria penetrating the roots of tomato and to enhance plant growth at 1-45 t/ha rates, while at higher dosages it was phytotoxic (Kaplan and Noe, 1993). The decomposition of organic matter helps in changing the physical, chemical and biotic condition of the soil. In addition, the improved soil structure promotes root growth of the host. Decomposed materials ultimately serve as nutrients for plants and crop yields favourably. In this section, an attempt has been made to select the most suitable and efficient organic wastes from the 15 different wastes like plant straws, green leaf 11

5 manure and animal manures tested for the management of root-knot nematode, M. incognita in chickpea var. Avrodhi. 7.2 MATERIALS AND METHODS Preparation and sterilization of soil mixture Soil, river sand and organic manure were mixed in a ratio of 3:1:1 (v/v/v), divided and kept in jute bags. Little water was poured into each bag to wet the soil after transferring them to an autoclave for sterilization at KPa for 2 minutes. Sterilized soil was allowed to cool down at room temperature before filling 15cm diameter clay pots with 1kg of sterilized soil. The study was carried out in three parts: EXPERIMENT 7A: With plant straws Growth and maintenance of test plant Seeds of chickpea (Cicer arietinum L.) cv. Avrodhi were surface sterilized with.1% mercuric chloride for 2min and then washed three times with distilled water. Five sterilized seeds of chickpea were then sown in 15cm diameter earthen pots containing 1kg sterilized soil and later thinned to one seedling per pot Preparation of nematode inoculum Root-knot nematode, Meloidogyne incognita culture was maintained as mentioned in Section-3. Second stage juveniles (J 2 ) Meloidogyne incognita race 2 were used as inoculum. Large number of M. incognita egg masses were handpicked, using sterilized forceps, from heavily infected tomato roots on which a pure culture of the nematode was maintained. These egg masses were washed in distilled water and then placed in 1cm diameter, 15-mesh coarse sieves containing crossed layers of tissue paper, placed in Petri plates containing water just enough to contact the egg masses and were kept in an incubator running at 25 C. The hatched juveniles (J 2 ) were collected from the Petri plates every 24h and fresh water was added. The concentration of second stage juveniles (J 2 ) of M. incognita in the water suspension was adjusted so that each milliliter contained 2±5 nematodes. 1ml of this suspension containing 2 freshly hatched juveniles were added to each pot containing a chickpea seedling. 12

6 Plant straws Ten grams of decomposed plant straws of Triticum aestivum L., Oryza sativa L., Zea mays L., Sorghum vulgare Pers. and Avena sativa L. were added around each seedling in the pots as shown in table 19a. Prior to use, straws of different plants has been allowed to decompose in separate containers for 6 months, with sufficient water being added at ten days intervals Inoculation technique For inoculation of M. incognita and the addition of decomposed plant straws, soil around the roots was carefully moved aside without damaging the roots. The inoculum suspension and decomposed plant straws were poured or placed around the roots and the soil was replaced. In control treatments, where no nematode inoculum and no plant straw were given, sterile water was added in equal volume to the seedlings Experimental design Straws of five different plants (Table 19a) were applied around the seedlings of chickpea in the presence as well as in the absence of M. incognita resulting 1 treatments. Uninoculated plants served as control. The experiment was set up in a completely randomized block design and each treatment was replicated five times. The pots were watered upto the soil capacity and kept on a glasshouse bench with air temperature ranging from 22±3 o C Observations The chickpea plants were terminated 9 days after the straw and nematode inoculation for determining the plant growth, chlorophyll content, nutrient status and nematode-related parameters (as discussed earlier in Section-2 and 3). The plants of each treatment were taken out from the pots and soil particles adhering to roots were removed by washing under tap water and properly labelled. Length of the plants was measured by measuring tape and fresh as well as dry weight of the plants were taken with the help of a physical balance. Excess water was removed by blotting paper before weighing shoots and roots separately. For dry weight determination, shoots and roots were kept in labelled envelopes and dried in a hot air oven running at 6 C for h before weighing. Chlorophyll content was estimated by the method of Arnon 13

7 Table 19. Organic wastes screened for the management of root-knot nematode, Meloidogyne incognita in chickpea A. Plant straws Common name Scientific name Family N (%) Wheat Triticum aestivum L. Poaceae.4 Rice Oryza sativa L. Poaceae.6 Maize Zea mays L. Poaceae.9 Jowar Sorghum vulgare Pers. Poaceae.7 Oat Avena sativa L. Poaceae 1.5 B. Green leaves of botanicals Common name Scientific name Family N (%) Neem Azadirachta indica A. Juss. Meliaceae 2.8 Bathua Chenopodium album L. Amaranthaceae 3.78 Aak Calotropis procera (Aiton) Asclepiadaceae 1.5 Water hyacinth Eichhornia crassipes (Mart.) Solms Pontederiaceae 1.8 Prickly poppy Argemone mexicana L. Papaveraceae 3.7 C. Animal wastes as manures Manure N (%) C:N ratio Poultry manure :1 Cow manure :1 Sheep manure :1 Horse manure :1 Goat manure 2. 18:1 14

8 (1949). Nutrient contents (N, P & K) were also estimated per 1g of fresh leaf weight. Nitrogen content of the shoot was estimated by the method of Lindner (1944), while phosphorus and potassium contents were estimated by the methods of Fiske and Subbarow (1925) and flame photometer, respectively Parameters studied After termination of the experiment, the following parameters were determined for each treatment: Plant length (cm) Plant fresh weight (g) Plant dry weight (g) Pods plant -1 Nodules plant -1 Chlorophyll content (mg g -1 fresh leaves) Nutrient contents (mg g -1 fresh leaves) Nematode-related parameters Plant growth and chemical parameters Plant growth and chemical parameters were studied by the methods mentioned in Section Nematode-related parameters Nematode related parameters in terms of nematode population (both in soil and root); number of galls root system -1 ; number of eggmasses root system -1 ; number of eggs eggmass -1 ; root-knot index (-5) and reproduction factor (pf/pi) were studied by the methods mentioned in Section EXPERIMENT 7B: With green leaves of botanicals Growth and maintenance of test plant Seedlings of chickpea (Cicer arietinum L.) cv. Avrodhi were raised and one seedling per pot was maintained as described above in Experiment 7A Preparation of nematode inoculum 15

9 Root-knot nematode, Meloidogyne incognita culture was maintained as mentioned above in Experiment 7A and in Section Green leaf manures Ten gram green leaves of botanicals Azadirachta indica A. Juss., Chenopodium album L., Calotropis procera (Aiton), Eichhornia crassipes (Mart.) Solms, and Argemone mexicana L. were added around each seedling in the pots as shown in table 19b. Prior to use, green leaves of different plants has been allowed to decompose in separate pots for 15 days, with sufficient water being added at 3 days interval Inoculation technique For inoculation of M. incognita and the addition of decomposed green leaves, soil around the roots was carefully moved aside without damaging the roots. The inoculum suspension and decomposed leaves were poured or placed around the roots and the soil was replaced. In control treatments, where no nematode inoculum and no green leaves were given, sterile water was added in equal volume to the seedlings Experimental design Decomposed green leaves of five different botanicals (Table 19b) were applied around the seedlings of chickpea in the presence as well as in the absence of M. incognita resulting 1 treatments. Uninoculated plants served as control. The experiment was set up in a completely randomized block design and each treatment was replicated five times. The pots were watered upto the soil capacity and kept on a glasshouse bench with air temperature ranging from 22±3 o C Observations The chickpea plants were terminated 9 days after the addition of botanicals and nematode inoculation for determining the plant growth, chlorophyll content, nutrient status and nematode-related parameters (as discussed earlier in Section-3) Parameters studied After termination of the experiment, the above parameters (as mentioned in Experiment 7A) were determined for each treatment. 16

10 Plant growth and chemical parameters Plant growth and chemical parameters were studied by the methods mentioned in Section Nematode-related parameters Nematode related parameters in terms of nematode population (both in soil and root); number of galls root system -1 ; number of eggmasses root system -1 ; number of eggs eggmass -1 ; root-knot index (-5) and reproduction factor (pf/pi) were studied by the methods mentioned in Section EXPERIMENT 7C: With animal manures Growth and maintenance of test plant Seedlings of chickpea (Cicer arietinum L.) cv. Avrodhi were raised and one seedling per pot was maintained as described above in Experiment 7A Preparation of nematode inoculum Root-knot nematode, Meloidogyne incognita culture was maintained as mentioned above in Experiment 7A and in Section Animal manures Ten grams each of poultry manure, cow manure, sheep manure, horse manure and goat manure were added around each seedling in the pots as shown in table 19c. Prior to use, different animal manures has been allowed to allowed to decompose in separate containers for 6 months, with sufficient water being added at ten days intervals Inoculation technique For inoculation of M. incognita and the addition of decomposed manures, soil around the roots was carefully moved aside without damaging the roots. The inoculum suspension and decomposed manures were poured or placed around the roots and the soil was replaced. In control treatments, where no nematode inoculum and no animal manure were given, sterile water was added in equal volume to the seedlings. 17

11 Experimental design Five different decomposed animal manures (Table 19c) were applied around the seedlings of chickpea in the presence as well as in the absence of M. incognita resulting 1 treatments. Uninoculated plants served as control. The experiment was set up in a completely randomized block design and each treatment was replicated five times. The pots were watered upto the soil capacity and kept on a glasshouse bench with air temperature ranging from 22±3 o C Observations The chickpea plants were terminated 9 days after the botanicals and nematode inoculation for determining the plant growth, chlorophyll content, nutrient status and nematode-related parameters (as discussed earlier in Section-2 and 3) Parameters studied After termination of the experiment, the above parameters (as mentioned in Experiment 7A) were determined for each treatment Plant growth and chemical parameters Plant growth and chemical parameters were studied by the methods mentioned in Section Nematode-related parameters Nematode related parameters in terms of nematode population (both in soil and root); number of galls root system -1 ; number of eggmasses root system -1 ; number of eggs eggmass -1 ; root-knot index (-5) and reproduction factor (pf/pi) were studied by the methods mentioned in Section Statistical analysis All the data in Experimant 7A, 7B and 7C were analyzed statistically by the method of Panse and Sukhatme (1985). Minimum difference required for significance (C.D.) at P=.1 and P=.5 was calculated by the ANOVA model 3 given in Appendix. 18

12 7.3 RESULTS EXPERIMENT 7A: With plant straws In the absence of M. incognita Plant length (cm) Different decomposed plant straws induced better growth in chickpea plants in terms of shoot, root and total length (Table 2a). Plants inoculated with A. sativa straw showed a significant increase in shoot length over control. Other decomposed straws failed to cause a significant increase in shoot length. Root length of chickpea plants was also promoted by decomposed straw of A. sativa. Root length in control as well as in plants inoculated with straws of T. aestivum, O. sativa and S. vulgare were significantly lower as compared to the ones treated with A. sativa straw. Highest increase in total length of chickpea plants was observed in case of A. sativa straw (24.%), followed by Z. mays (14.6%), S. vulgare (12.%), O. sativa (8%) and T. aestivum (5.%) (Table 2a and Fig. 13) Plant fresh weight (g) Plant fresh weight was studied in terms of shoot, root and total fresh weight of chickpea plant (Table 2a). Straw of A. sativa brings about a significant increase in shoot fresh weight as compared to other plant straws and control treatments. Lowest fresh weight was observed in shoots of plants treated with T. aestivum straw. 13). Root fresh weight showed the similar trend as that of shoot fresh weight (Fig. Total fresh weight of chickpea plants got improved by inoculation with straw of A. sativa (26.19%). Straw of T. aestivum, O. sativa, Z. mays, and S. vulgare failed to cause a significant increase in total fresh weight of plants over control (Table 2a) Plant dry weight (g) 19

13 Dry weight was also studied in terms of shoot and total dry weight of chickpea plants (Fig. 13). Significantly highest shoot dry weight was reported in plants treated with decomposed straw of A. sativa than all other straws and control treatment. Root dry weight of plants showed the similar trend as that of shoot dry weight. Highest root dry weight (3.86%) was observed in A. sativa straw treated plants. A. sativa straw proved to be significantly superior to other decomposed plant straws in increasing the total plant dry weight. Total dry weight was maximum while inoculation with A. sativa straw (28.3%) followed by Z. mays (12.5%), S. vulgare (9.47%), O. sativa (5.41%) and T. aestivum (2.83%) (Table 2a) Pods plant -1 Decomposed plant straws of O. sativa, Z. mays, S. vulgare and A. sativa significantly increase the number of pods over control. Straw of T. aestivum did not cause a significant increase in number of pods plant -1. Highest number of pods (51) were recorded in A. sativa straw as compared to other treatments (Table 2a) Nodules plant -1 All the straws brings about a significant increase in the number of nodules plant -1. A. sativa straw observed highest and T. aestivum lowest number of nodules plant -1 i.e. 1 and 5 respectively (Table 2a) Chlorophyll content (mg g -1 ) fresh leaves The highest increase in chlorophyll content was observed in plants inoculated with straw of A. sativa (2.48%), followed by Z. mays (11.78%) S. vulgare (8.62%), O. sativa (5.49%) and T. aestivum (2.54%). Significant increase was reported in case of A. sativa straw only (Table 21a and Fig. 13) Nutrient contents (N, P & K) (mg g -1 ) fresh leaves Different straw increased the nutrient contents (N, P & K) in chickpea plants over control but the increase was not significant. Nutrient contents (N, P & K) were significantly increased in plants treated with A. sativa straw i.e %, 3.42% and 22.4% respectively (Table 21a and Fig. 13). 2

14 Plant length (cm) Shoot Root Chlorophyll content (mg g -1 ) Plant fresh weight (g) Shoot Root N P K Nutrient contents (mg g -1 ) 1 8 Shoot Root Treatments. Plant dry weight (g) Treatments T1 = Control; T2 = T. aestivum; T3 = O. sativa; T4 = Z. mays; T5 = S. vulgare; T6 = A. sativa Fig. 13 Effect of different plant straws on the growth parameters, chlorophyll content and nutrient status of chickpea plant 21

15 In the presence of M. incognita Inoculation with M. incognita caused a significant reduction in all the growth parameters compared with uninoculated control Plant length (cm) Plant length was studied in terms of shoot, root and total length of chickpea plants (Table 2b). Different plant straws brings about an increase in the shoot length of nematode-inoculated plants. Significant increase was observed in case of A. sativa straw with M. incognita only (Fig.14). Root length shows the similar trend as that of shoot length. Highest reduction in root length by M. incognita was observed in O. sativa straw (15.42%) as compared to other straws. A. sativa straw promoted the total length of chickpea plants inoculated with M. incognita over all other plant straws and control. Highest total length was observed in A. sativa straw (23.5%), followed by Z. mays (13.48%), S. vulgare (1.74%), O. sativa (8.25%) and T. aestivum (4.42%) with nematode over nematode-inoculated untreated plants (Table 2b and Fig. 14). M. incognita caused 13.45%, 13.%, 14.6%, 14.18% and 13.56% reduction in total length of T. aestivum, O. sativa, Z. mays, S. vulgare and A. sativa treated plants Plant fresh weight (g) Plant fresh weight was studied in terms of shoot, root and total fresh weight of chickpea plant (Table 2b). M. incognita caused 2.6% decrease in shoot fresh weight over uninoculateduntreated control plants. Shoot fresh weight in the presence of nematode was increased by all plant straws as but the significant increase was caused only by straw of A. sativa and Z. mays as compared to nematode-inoculated untreated plants. Root fresh weight showed the similar trend as that of shoot. Highest fresh weight was observed in plants treated with A. sativa (24.57%) with M. incognita. 22

16 Total fresh weight of plants were significantly increased by A. sativa (25.4%) and Z. mays (15.51%) over nematode-inoculated untreated plants. Lowest increase was observed in T. aestivum straw, i.e. 5.68% (Table 2b and Fig. 14). Reduction caused by M. incognita in case of T. aestivum, O. sativa, Z. mays and S. vulgare was at par with each other Plant dry weight (g) Plant dry weight was also studied in terms of shoot, root and total dry weight of chickpea plants (Table 2b). Significant increase in shoot dry weight was reported in case of A. sativa and Z. mays with M. incognita over all other plant straws treated and nematode-inoculated untreated plants. Root dry weight showed the similar trend as that of shoot dry weight. M. incognita significantly reduced the root dry weight as compared to the plants treated with different straws in the absence of nematode. Straws of T. aestivum, O. sativa and S. vulgare failed to cause a significant increase in the total dry weight of chickpea plants inoculated with M. incognita. A. sativa was most efficient in overcome the reduction caused by M. incognita followed by Z. mays and cause 25.66% and 16.7% increase in total dry weight over nematodeinoculated untreated control plants (Table 2b and Fig. 14) Pods plant -1 M. incognita decreased the number of pods plant -1 over nematode untreated plants. Lowest reduction by M. incognita was recorded in A. sativa (21.57%) and highest in T. aestivum (37.14%) (Table 2b). Different plant straws significantly increase the pods as compared to nematode inoculated-untreated plants. 23

17 Table 2. Effect of different plant straws on the growth parameters of chickpea plant in the presence and absence of root-knot nematode, Meloidogyne incognita Treatments Plant length (cm) Plant fresh weight (g) Plant dry weight (g) Pods Shoot Root Total Shoot Root Total Shoot Root Total plant -1 a) Without M. incognita Control 43.64± ± ± ± ± ± ± ± ± ± ±.2 T. aestivum 45.78± ± ± ± ± ± ± ± ± ± ±.25 O. sativa 47.15± ± ± ± ± ± ± ± ± ± ±.3 Z. mays 5.2± ± ± ± ± ± ± ± ± ± ±.4 S. vulgare 48.98± ± ± ± ± ± ± ±.9 8.9± ±2.1 7.±.35 A. sativa 54.12± ± ± ± ± ± ± ± ± ± ±.5 C.D. (P=.5) C.D. (P=.1) b) With M. incognita M. incognita 37.85± ± ± ± ± ± ± ± ± ±.9 2.±.1 T. aestivum 39.62± ± ± ± ± ± ± ± ± ±1.1 2.±.1 O. sativa 41.59± ± ± ± ± ± ± ± ± ±1.3 3.±.15 Z. mays 43.7± ± ± ±2. 1.8±.5 5.5± ± ± ± ± ±.35 S. vulgare 42.6± ± ± ± ± ± ± ± ± ± ±.25 A. sativa 46.81± ± ± ± ± ± ± ± ±.41 4.±2. 8.±.4 C.D. (P=.5) C.D. (P=.1) Data mean±sd of five replicates Nodules plant -1 1

18 Plant length (cm) Shoot Root Chlorophyll content (mg g -1 ) Plant fresh weight (g) Shoot Root N P K Nutrient contents (mg g -1 ) 7 6 Shoot Root Treatments. Plant dry weight (g) Treatments T1 = Control; T2 = T. aestivum; T3 = O. sativa; T4 = Z. mays; T5 = S. vulgare; T6 = A. sativa Fig. 14 Effect of different plant straws on the growth parameters, chlorophyll content and nutrient status of chickpea plant infected with root-knot nematode, Meloidogyne incognita 1

19 Nodules plant -1 Decomposed straw of all the plants brings about a significant increase in the number of nodules plant -1 over nematode-inoculated untreated plants except T. aestivum which possess same number of nodules as in control i.e. 2. Highest nodule number (8) was observed in case of A. sativa (Table 2b). Reduction caused by M. incognita in T. aestivum and Z. mays treated plants was same and highest reduction in nodules number was recorded in plants treated with O. sativa straw (6%) over nematode-uninoculated plants Chlorophyll content (mg g -1 fresh leaves) M. incognita significantly decrease the chlorophyll content (24.2%) over uninoculated control plants. Nematode influence in plants treated with straws of T. aestivum, Z. mays and S. vulgare was at par. A. sativa and Z. mays with M. incognita caused a significant increase in chlorophyll content of chickpea plants over all other treatments (Fig. 14). Highest increase in chlorophyll content of nematode inoculated plants was recorded in A. sativa straw (23.45%). T. aestivum, O. sativa and S. vulgare did not cause a significant increase in the chlorophyll content over nematodeinoculated untreated plants (Table 21b) Nutrient contents (N, P & K) (mg g -1 fresh leaves) Nutrient contents (N, P and K) were adversely affected by the presence of root-knot nematode, M. incognita. A. sativa straw was the most efficient in overcome the reduction caused by the nematode, followed by Z. mays and 25.6%N, 23.75% P and 2.78%K were recorded in plants treated with A. sativa and M. incognita (Table 21b and Fig. 14). No significant increase in nutrient contents was reported in other straws over nematode-inoculated untreated plants Root-knot development The effect of different plant straws on the root-knot development of M. incognita has been studied in terms of nematode population (both in soil and root), number of galls root system -1, number of eggmasses root system -1, number of eggs eggmass -1, root-knot index (-5) and reproduction factor (pf/pi) (Table 21b and Fig. 15). 2

20 a Nematode population All the decomposed straws of different plants significantly reduced the nematode population of M. incognita in soil as well as in root. Highest reduction was observed in case of straw of A. sativa, followed by Z. mays, S. vulgare, O. sativa and T. aestivum (Table 21b and Fig. 15) b Number of galls root system -1 Number of galls were reduced significantly when plants were inoculated separately with straws of different plants. However, reduction in galling was maximum in case of A. sativa (41.9%) (Table 21b and Fig. 15) c Number of eggmasses root system -1 Reduction in number of eggmasses was significant in all the straws but the lowest number of eggmasses root system -1 were observed in case of A. sativa straw (48) (Table 21b and Fig. 15) d Number of eggs eggmass -1 Different straws brings about a significant reduction in the fecundity of M. incognita. Reduction was maximum in A. sativa straw > Z. mays > S. vulgare > O. sativa > T. aestivum (Table 21b and Fig. 15) e Root-knot index (-5) Lowest root-knot index (1) was observed in case of A. sativa straw. T. aestivum showed the same root-knot index as that of nematode-inoculated untreated plants, i.e. 4 (Table 21b and Fig. 15). A. sativa was most efficient in overcome the reduction caused by M. incognita, thus having lowest root index i.e f Reproduction factor (pf/pi) Application of different decomposed straws reduced the reproduction rate of M. incognita. Lowest reproduction was observed in A. sativa straw (7.5), followed by Z. mays (8.4), S. vulgare (8.71), O. sativa (9.5) and T. aestivum (9.5) (Table 21b and Fig. 15). 3

21 Table 21. Effect of different plant straws on the chlorophyll content, nutrient status and root-knot development of Meloidogyne incognita in chickpea plant Treatments Chlorophyll content (mg g -1 ) Nutrient contents (mg g -1 ) Nematode population No. of galls N P K Soil Root root system -1 No. of eggmasses root system -1 No. of eggs eggmass -1 Root-knot index (-5) Reproduction factor (pf/pi) a) Without M. incognita Control 2.42± ±.13.24± ±.1.±..±..±..±..±...±. T. aestivum 2.463± ± ± ±.1.±..±..±..±..±...±. O. sativa 2.534± ± ± ±.1.±..±..±..±..±...±. Z. mays 2.685± ± ± ±.11.±..±..±..±..±...±. S. vulgare 2.69± ± ± ±.1.±..±..±..±..±...±. A. sativa 2.894± ± ± ±.12.±..±..±..±..±...±. C.D. (P=.5) ±..±..±..±..±...±. C.D. (P=.1) ±..±..±..±..±...±. b) With M. incognita M. incognita 1.825± ±.12.16± ±.8 11,915± ± ±1.5 84± ± ±.61 T. aestivum 1.956± ± ± ±.8 9,413±471 19± ±8.3 68± ± ±.48 O. sativa 2.29± ± ± ±.8 8,936± ±9. 158±7.9 65± ± ±.45 Z. mays 2.133± ± ± ±.9 8,34± ± ±7.3 59±2.9 18± ±.42 S. vulgare 2.81± ± ± ±.9 8,698± ± ±7.6 62± ± ±.44 A. sativa 2.253± ± ± ±.9 7,89± ±7. 122±6.1 48±2.4 89± ±.35 C.D. (P=.5) C.D. (P=.1) Data mean±sd of five replicates 1

22 Nematode population Soil ( 1) Root No. of eggs eggmass No. of galls root system Root-knot index (-5) 1 14 No. of eggmasses root system Reproduction factor (pf/pi) Treatments Treatments T1 = Control; T2 = T. aestivum; T3 = O. sativa; T4 = Z. mays; T5 = S. vulgare; T6 = A. sativa Fig. 15 Effect of different plant straws on the root-knot development of Meloidogyne incognita in chickpea plant 1

23 7.3.2 EXPERIMENT 5B: With green leaf manures of botanicals In the absence of M. incognita Plant length (cm) Decomposed green leaves of botanicals A. indica, C. album, C. procera, E. crassipes and A. mexicana were highly effective on chickpea plant length in terms of shoot, root and total length (Table 22a). Shoot length was significantly increased by the addition of green manure of A. indica, C. album, E. crassipes and A. mexicana over untreated control. C. procera failed to cause a significant increase in the shoot length of chickpea plants. Root length showed the similar trend as that of shoot length. Highest root length was reported in plants treated with C. album leaves. Maximum enhancement in total length of chickpea plants was observed in case of C. album (27.%), followed by A. mexicana (23.19%), A. indica (19.69%) and E. crassipes (16.28%). No significant increase in total plant length was observed in case of C. procera (Table 22a and Fig. 16) Plant fresh weight (g) Plant fresh weight was studied in terms of shoot, root and total fresh weight of chickpea plants (Table 22a). Maximum increase in shoot fresh weight (28.9%) was reported in plants treated with the botanical C. album over control. Increase was not significant in case of C. procera. Root fresh weight of chickpea plants showed the similar trend as that of shoot fresh weight. Application of decomposed leaves of different plants as botanicals increased the total fresh weight of chickpea plants but the increase was not significant in case of C. procera. Highest increase in total fresh weight of chickpea plants were observed in C. album (29.15%), followed by A. mexicana (24.37%), A. indica (2.72%), and E. crassipes (17.19%) (Table 22a and Fig. 16). 2

24 Plant dry weight (g) Plant dry weight was also studied in terms of shoot, root and total dry weight of chickpea plants. Shoot dry weight was significantly increased over control plants when inoculated with A. indica, E. crasssipes, C. album and A. mexicana (Table 22a). However, the highest increase was recorded in case of C. album (28.72%). Root dry weight of chickpea plants showed the similar trend as that of shoot dry weight (Fig. 16). C. album caused a maximum enhancement in total dry weight of chickpea plants (28.91%), followed by A. mexicana (24.97%), A. indica (21.52%) and E. crassipes (17.96%). Increase was not significant in case of C. procera as compared to control (Table 22a and Fig. 16) Pods plant -1 Different decomposed leaves increased the pods number in plants over untreated control but the increase was not significant in case of C. procera. Highest number of pods plant -1 was recorded in C. album i.e. 53 and lowest in C. procera i.e. 35 (Table 22a) Nodules plant -1 All the botanicals brings about a significant increase in number of nodules plant -1 except C. procera. Highest nodulation was reported in C. album (12) > A. mexicana > A. indica > E. crassipes > C. procera (Table 22a) Chlorophyll content (mg g -1 fresh leaves) Significant increase in chlorophyll content of chickpea plants was observed in case of botanical C. album followed by A. mexicana and A. indica. E. crassipes and C. procera failed to bring a significant increase in the same (Table 23a and Fig. 16) Nutrient contents (N, P & K) (mg g -1 fresh leaves) Application of decomposed leaves of botanicals C. album, A. mexicana, A. indica and E. crassipes caused a significant increase in N, P and K contents of 3

25 Plant length (cm) Shoot Root Chlorophyll content (mg g -1 ) Plant fresh weight (g) Shoot Root N P K Nutrient contents (mg g -1 ) 1 8 Shoot Root Treatments Plant dry weight (g) Treatments T1 = Control; T2 = A. indica; T3 = C. album; T4 = C. procera; T5 = E. crassipes; T6 = A. mexicana Fig. 16 Effect of green leaves of different botanicals on the growth parameters, chlorophyll content and nutrient status of chickpea plant 4

26 chickpea plants over control but the difference lies that E. crassipes failed to bring a significant increase in P and K contents of the plants. However, the highest increase in nutrient contents were observed in case of C. album treated plants (38.6%N, 31.25% P and 23.44%K) (Table 23a and Fig. 16) In the presence of M. incognita In general, M. incognita reduced all the growth parameters, chlorophyll and nutrients contents as compared to uninoculated control Plant length (cm) Plant length (cm) was studied in terms of shoot, root and total plant length of chickpea plants (Table 22b and Fig. 17). Leaves of botanical C. album, A. mexicana and A. indica significantly overcome the loss caused by M. incognita. However, the highest increase over nematode-inoculated plants was observed in case of C. album (24.78%). C. procera and E. crassipes also suppress the nematode effect and increase the shoot length but the increase was not significant. Reduction in root length of chickpea plants was observed in case of leaves of all plants while inoculation with M. incognita. C. album and A. mexicana significantly overcome the reduction of nematode and cause highest increase over nematode inoculated-untreated plants. M. incognita significantly reduced the total length of plants. However, the lowest reduction by M. incognita in total length of chickpea plant was observed in case of C. album (14.72%), followed by A. mexicana (16.2%), A. indica (16.75%), E. crassipes (17.68%) and C. procera (18.8%) over nematode uninoculated plants (Table 22b) Fresh weight (g) Plant fresh weight was studied in terms of shoot, root and total fresh weight of chickpea plants (Table 22b). M. incognita reduced the shoot fresh weight by 2.6% over nematode uninoculated control plants. C. album reduced the loss caused by M. incognita to a 5

27 highest extent and caused 25.96% increase in shoot fresh weight over nematodeinoculated plants. Root fresh weight also decreased by the inoculation of root-knot nematode, M. incognita. C. album followed by A. mexicana and A. indica were able to significantly overcome the reduction caused by M. incognita. C. procera and E. crassipes with nematode did not cause a significant increase in root fresh weight of chickpea plants over nematode-inoculated control plants. For overall fresh weight, the trend was the same as that for shoot and root fresh weight. Reduction by M. incognita in A. indica and C. album was at par as compared to plants in the absence of nematode. C. album followed by A. mexicana and A. indica suppress nematode infection and cause 25.75%, 21.39% and 17.58% increase in total fresh weight over nematode inoculated-untreated plants (Tabel 22b and Fig. 17) Plant dry weight (g) Plant dry weight was studied in terms of shoot, root and total dry weight of chickpea plants (Table 22b and Fig. 17). Shoot dry weight decreased significantly in plants inoculated with M. incognita. C. album, A. mexicana, A. indica, E. crassipes and C. procera overcome the loss caused by the nematode and increase the shoot fresh weight but the increase was not significant in case of E. crassipes and C. procera treated plants. Root dry weight showed the similar trend as that of shoot dry weight (Fig. 17). M. incognita reduced the root dry weight by 2.37% over nematode uninoculated control plants. C. album reduced the loss caused by M. incognita and caused 28.68% increase in root dry weight over nematode-inoculated untreated plants. Reduction by M. incognita in C. album, A. mexicana and A. indica treated plants was at par over botanicals treated plants in the absence of nematode. C. album followed by A. mexicana and A. indica suppressed the effect of M. incognita to a significant extent and cause 25.96%, 22.25% and 18.8% increase over nematodeinoculated untreated chickpea plants (Table 22b) Pods plant -1 6

28 M. incognita caused 13.45%, 13.%, 14.6%, 14.18% and 13.56% reduction in total length of T. aestivum, O. sativa, Z. mays, S. vulgare and A. sativa treated plants M. incognita reduced the number of pods plant -1 in C. album (18.86%), A. mexicana (19.56%), A. indica (23.8%), E. crassipes (33.33%) and C. procera (4.%) treated plants over nematode-uninoculated botanicals treated plants. C. album treated plants showed highest number of pods (43) > A. mexicana > A. indica > E. crassipes > C. procera (Table 22b) Nodules plant -1 Decomposed leaves of all the plants significantly reduced the effect of M. incognita and increase the nodules number of the plant over nematode-inoculated untreated control. However, highest nodule number was observed in C. album i.e. 9 and lowest in C. procera i.e. 3 (Table 22b). Reduction caused by M. incognita in C. album and A. indica was at par (25%) Chlorophyll control (mg g -1 fresh leaves) M. incognita significantly reduced the chlorophyll content in chickpea plants. Reduction was lowest in case of C. album (22.68%) over nematode-uninoculated botanical treated plants. Different botanicals reduced the effect of M. incognita and brings about an increase in the chlorophyll content of chickpea plants. However, the increase was significant in case of C. album (25.14%), A. mexicana (2.22%) and A. indica (16.39%) over nematode-inoculated untreated plants (Table 23b and Fig. 17) Nutrient contents (N, P & K) (mg g -1 fresh leaves) Different botanicals reduced the effect of M. incognita and brings about an increase in the nutrient contents (N, P & K) of chickpea plants. However, the increase was significant in case of C. album followed by A. mexicana and A. indica over nematode-inoculated untreated plants. C. album was most efficient in reducing the loss caused by nematode and cause a significant increase of 27.83%, 25% and 21.43% in N, P and K respectively over nematode-inoculated untreated chickpea plants (Table 23b and Fig. 17). 7

29 Table 22. Effect of green leaves of different botanicals on the growth parameters of chickpea plant in the presence and absence of rootknot nematode, Meloidogyne incognita Treatments Plant length (cm) Plant fresh weight (g) Plant dry weight (g) Pods Shoot Root Total Shoot Root Total Shoot Root Total plant -1 a) Without M. incognita Control 43.64± ± ± ± ± ± ± ± ± ± ±.2 A. indica 52.35± ± ± ± ± ± ± ± ± ±2.1 8.±.4 C. album 55.62± ± ± ± ±.71 7.± ± ± ± ± ±.6 C. procera 5.26± ± ± ± ± ± ± ± ± ± ±.25 E. crassipes 5.95± ± ± ± ± ± ± ± ± ± ±.3 A. mexicana 53.91± ± ± ± ± ± ± ± ± ±2.3 1.±.5 C.D. (P=.5) C.D. (P=.1) b) With M. incognita M. incognita 37.85± ± ± ± ± ± ± ± ± ±.9 2.±.1 A. indica 43.61± ± ± ± ± ± ± ± ± ±1.6 6.±.3 C. album 47.23± ± ± ± ± ± ± ± ± ± ±.45 C. procera 4.85± ± ± ± ± ± ± ±.7 7.8± ±1.5 3.±.15 E. crassipes 41.86± ± ± ± ± ± ± ± ± ±1.3 4.±.2 A. mexicana 45.19± ± ± ± ± ± ± ± ±.4 37.± ±.35 C.D. (P=.5) C.D. (P=.1) Data mean±sd of five replicates Nodules plant -1 1

30 Plant length (cm) Shoot Root Chlorophyll content (mg g -1 ) Plant fresh weight (g) Shoot Root N P K Nutrient contents (mg g -1 ) Plant dry weight (g) Shoot Root Treatments. Treatments T1 = Control; T2 = A. indica; T3 = C. album; T4 = C. procera; T5 = E. crassipes; T6 = A. mexicana Fig. 17 Effect of green leaves of different botanicals on the growth parameters, chlorophyll content and nutrient status of chickpea plant infected with root-knot nematode, Meloidogyne incognita 1

31 Root-knot development The effect of green leaves of different botanicals on the root-knot development of M. incognita has been studied in terms of following parameters: a Nematode population All the botanicals brings about a significant reduction in the population of M. incognita in soil as well as in the roots of chickpea plant. However, highest reduction was observed in plants treated with C. album (Table 23b and Fig. 18) b Number of galls root system -1 Decomposed leaves of different botanicals significantly reduced the number of galls root system 1. Lowest number of galls were observed in case of C. album (82), followed by A. mexicana, A. indica, E. crassipes and C. procera (Table 23b and Fig. 18) c Number of eggmasses root system 1 Number of eggmasses were significantly reduced by the addition of botanicals. However, the highest reduction was observed in plants treated with the leaves of C. album (32) (Table 23b and Fig. 18) d Number of eggs eggmass 1 Fecundity (number of eggs eggmass 1 ) decreased by the application of green leaves of botanicals. Lowest number of eggs were recorded in plants treated with C. album (61), followed by A. mexicana (7), A. indica (85), E. crassipes (94) and C. procera (13) (Table 23b and Fig. 18) e Root-knot index (-5) Root-knot index (RKI) of E. crassipes, C. procera was same as that of nematode-inoculated untreated plants i.e. 4. Lowest RKI (1) was observed in plants treated with C. album (Table 23b and Fig. 18) f Reproduction factor (pf/pi) Leaves of different botanicals significantly reduced the reproduction rate of M. incognita. However, the reproduction was lowest (4.8) in case of C. album followed 2