ASSESSMENT OF REACTION OF COMMON MAIZE GENOTYPES TO NORTHERN LEAF BLIGHT. DAVID M WAMUYU A22/1771/2010 SUPERVISOR: Dr. WILLIAM M.

Transcription

1 ASSESSMENT OF REACTION OF COMMON MAIZE GENOTYPES TO NORTHERN LEAF BLIGHT DAVID M WAMUYU A22/1771/2010 SUPERVISOR: Dr. WILLIAM M. MAINA 1

2 INTRODUCTION Northern leaf blight of maize is a major foliar disease in Kenya. The disease is caused by Exserohilum turcicum. Causes leaf necroses and premature death of foliage which reduces the fodder value. Most of the composites and hybrids, which are being cultivated commercially, are susceptible to Northern leaf blight. TLB in maize can cause yield loss in the range of 13.6 to 56.0 % depending upon the genotype. Therefore, there is considerable interest to evaluate the reaction of various maize genotypes that can be used to help in managing the disease. 2

3 JUSTIFICATION TLB in particular has proven to be especially damaging to maize production. The avoidable yield loss caused by TLB average at 14.5%,which is the same average amount Kenya imports. Controlling this disease has very big implication especially to small scale farmers who are resource poor. This project focuses on using plant resistance to provide control solutions within the seed itself. 3

4 OBJECTIVE General objective To improve on the management of northern leaf blight, thus helping to increase maize productivity. Specific objective To evaluate the reaction of maize genotype to Northern leaf blight. To determine the aggressiveness of the disease to various maize genotypes. 4

5 METHODOLOGY Materials and methods Sources of seeds- CIMMYT Kiboko, under the (IRMA) project. The trial comprised of 19 genotypes, and carried out in UON UPPER KABETE FIELD STATION. Experimental design - The common experimental design used was randomized complete block design (RCBD). Procedure for planting-field cultivation was done early enough followed by harrowing using a tractor before planting. layout - Planting was done on 3 metres long rows, 0.75 metres between rows, 0.25 metres between hills, and two seeds per hill to be thinned to one plant per hill 5

6 Crop husbandry Cont... Thinning - The trial was planted with 2 seeds. At about four weeks after planting, the trial was thinned to one plant per planting station Basal fertilization - 10 gm of DAP fertilizer along side each hill was applied. Top dressing - (CAN) at the rate of 10 gm per hill at near high Weed control - Weeding was done using a jembe. Assessment of disease Data analysis - Data collected included; disease severity scores and disease incidence. Statistical analysis of the data was done using the GENSTAT. 6

7 VARIETY DISEASE INCIDENCE NO. OF PLANT INFECTED MEAN CKIR CKIR CKIR CKIR CKIR CKIR CKIR CKIR WH CKIR CKIR CKIR CKIR CKIR CKIR GITHIGU CKIR CV LSD GRAND MEAN

8 DISCUSSION The variety CKIR12019 was the most resistant with disease incidence of 30% and CKIR12010 was the most susceptible with disease incidence of 71%. 8

9 VARIETY DISEASE INCIDENCE NO OF LEAVES INFECTED MEAN CKIR CKIR CKIR CKIR CKIR WH CKIR CKIR CKIR CKIR CKIR CKIR CKIR GITHIGU CKIR CKIR CKIR CV 30 LSD GRAND MEAN

10 DISCUSSION Variety CKIR12019 was the most resistant with disease incidence of 15% and CKIR12003 was the most susceptible with the disease incidence of 39%. 10

11 DISEASE SEVERITY VARIETY MEANS CKIR WH CKIR CKIR CKIR CKIR CKIR CKIR CKIR CKIR CKIR CKIR CKIR CKIR CKIR GITHIGU 1.75 CKIR CV LSD 0.82 GRAND MEAN

12 DISCUSSION Variety CKIR12019 was the most resistant with disease severity of 0.57 and GITHIGU was the most susceptible with disease severity of

13 CONCLUSION AND RECOMMENDATION From the experiment conducted, it was established that TLB was prevalent in the area. The number of diseased leaves and plants infected varied with the maize genotype. There were genotypes with stable genes for TLB resistance. Maize genotype CKIR12019 had few infected plants and few lesions was rated as the most resistant whereas GITHIGU was found to be highly susceptible with large lesions and extensive chlorosis. Plants like CKIR12019, CKIR12016, WH505, CKIR12050,CKIR12013, CKIR12004,CKIR12010 and 614 were highly vigorous and showed moderate resistance to TLB. It is strongly believed that given all the advantages of host plant resistance approach, offers the best option for dealing with the problem of TLB. 13

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