Cooperative Extension Service. College of Tropical Agriculture & Human Resources / University of Hawaii. CIRCULAR / Evaluation1of .

Transcription

1 v Cooperative Extension Service. College of Tropical Agriculture & Human Resources University of Hawaii. CIRCULAR t t I 2 ".J b ) ~ J ( I I J Evaluation1of, Papaya Lines andcu!fl:jral Practices I I J ' ). ) at Moloaa, Islclild of Kauai, Hawaii, ) I r ~. ~ I. :7, 1.',-' I, Wa~ren Y. J. 'Vee Terry T:Sekioka Henry Y. Nakasone - Dennis K~J~ehara Jeri J. Ooka Ernest K. Akamine I If 1. I I.. I

2 "-, ' ~, ' ( I-.' 1 ( ), k!.,;-: '" c, ' ( ',j ", ( ' ) ~. ( ".', I, -I I ' ", I (. ' r I ','"..- J - I - ' '. t. f : )1 r: ' y,- " " I,', ', ' '. v.. f. --;- -.. " ' ''- -:.~... I..... " '.. ' I ',--...,: '!. ', ; -,,.,. r : 's-, ), ; ",). " ", ' J.: --, I "-.. ' '...-. ) -,.,. i ', ' 'J ",, rr ') ', -< ', T~E 'AUTHORS ~ ' I.',.I" " ' ~ ( -,,I,, -, _ r -, _.,V '. - ( :-', ' - " ) r -, J, ). ) '-.',, i ;' ' 1'. ;.. ', ) >(' 'YA, RR~N X~! " Y~E is ~~ eci ~lis t i,ij ijp ~t ~ G~ltU!~, EmeritusvUniversity','~ i ) '-'~,., ~ of Hawaii ',(" - I 'i " J ' ' '.f -,',,. - I,I ' -.' ' " ',', j ->,, '_ '--~ TERRY T. SEKIOKA is Associate Horticulturist, University "of HaW'aii, -.:.. I ; ".., }j " ~.., '1".:.....r, J '~~;', Island of.kauai.., r",, ",_,',~, <, '-', ~-. '1 ' :,, ",'(! H EN RY 'YoNAKASO'NE IS'Professor and Hortictilturist; Universityco f: I ~ "" I' ',: H ".; ' " " -! ' : r- E ", " ' r awall. '_ ', -.:,,._., ~ ' ),D EN_NIS,K. 1~EHAR~.i~ Co dnty-e?c.t~si,dn,:~gent ; }slanc'i ofkauai. ;'" -. ~ '. r JE~I) : 'OJ~ K A is 'Assistant Plant Pathologist, Universi ty of Hawaii, ' j..., 1 - II } d f " san,o K,,'aUaI. -. '. ' ", '," ' -" ',, ", ' " :.,,' " r: ;- ERNEST K. AKAMINE is' Pl'an t' Physiologist, Emeritus, University of ' ".Hawaii: :---. ; f" ' ' " ~',,[ -, ( <; ' '.; ' -, ' ' " ' ',',.J :"!

3 CONTENTS Page Introduction 3 Materials and Methods 4 Part A-Evaluation and Selection 4 Results and Discussion 5 Part B-Cultural Demonstrations 9 Block 1- Results and Discussion 9 Effects of Spacing and Irrigation Levels on Tree Characters, 9 Effects of Spacing and Irrigation Levels on Average Fruit Weight 9 Effects of Spacing and Irrigation Levels on Percent Total Soluble Solids 11 Effects of Fertilizer Treatments with Two Lim e Levels on Fruit Count 11 Interaction of Spacing, Fertilizer, Lim e, and Irrigation 11 Block II-Results and Discussion 17 Effects ofmulch, Fumigation, and Propagation Methods on Tree Characters Effect of "Jorgen " on Fruit Set and Total Soluble Solid s Effects of Dry (F 1 Table 6) and Liquid Fertilizer Combinations 19 Summary and Conclusions 19 Cultural Recommendations 20

4 ACKNOWLEDGMENTS The evaluation of papaya lines and cultural practices at the Moloaa Project by the College of Tropical Agriculture and Human Resources, University of Hawaii, was initiated as a result of the efforts of individuals and government agencies concerned with the development of a viable papaya industry on the Island of Kauai. In particular, Edward W. Y. Goo of Moloaa Farmers' Cooperative, Henry T. Osano of Best Fruits, and Shokun Kobashigawa, a conscientious and successful papaya grower, are recognized for their strong support. Through their efforts and others, the assistance of John Farias, William H. Agena, and Robert A. Souza of the Hawaii State Department of Agriculture was obtained. The Kauai Task Force and Calvin F. S. Lee of the Hawaii State Department of Planning and Economic Development also were involved in the partial funding and evaluation of the economic progress of the project as it would affect commercial papaya production. The donation of the liquid fertilizer for the trial, from George Hiyane of Brewer Chemical Corporation, is gratefully acknowledged. The authors wish to acknowledge the assistance of other members of the College of Tropical Agriculture and Human Resources who served in an advisory capacity: Roger T. Watanabe, for advising us about lime and phosphate requirements under Moloaa conditions. Minoru Awada, for advising us about fertilizer and moisture requirements. Albert P. Martinez, for his advice on nematode control. Frank H. Haramoto, for advice on controlling mites. Roy K. Nishimoto, for his suggestions on weed control. Harris M. Gitlin and I-pai Wu, for their assistance in setting up the irrigation system.

5 EVALUATION OF PAPAYA LINES AND CULTURAL PRACTICES AT MOLOAA, ISLAND OF KAUAI, HAWAII Warren V. J. Vee, Terry T. Sekioka, Henry V. Nakasone; Dennis K. Ikehara, Jeri J. Ooka, Ernest K. Akamine INTRODUCTION Th e land at Moloaa, Island of Kauai, Hawaii, was intensely cultivated with sugarcane or pineapples for more than 50 years. When thes e crops were phas ed out in 1973 because of insufficient returns, small farmers supported with Hawaii Sta te funds attem pt ed to grow papayas in the area. Being unfamiliar with the area, the growers requested assistance from the State. Under a joint agreement involving members of the Moloaa Farmers' Cooperative, the University of Hawaii 's College of Tropical Agriculture and Human Resources, and th e Kauai Task Force (State supported), the Horticulture Department ofthe College was given the responsibility to: (I) develop cultivars adapted to Moloaa by evaluating advanced hybrid lines and segregating populations, and (2) develop a model papaya dem onstration farm, using the latest cultural practices and technologies available and obtain information that would be helpful to the growers. Other departments in the College that were involved in the Project included Agricultural Engineering, Plant Pathology, Plant Physiology, and the Soils section of the Agronomy and Soils Department. Because tim e was important to th e grow ers and the Proj ect would take approximately three years to complete, periodic field day s were scheduled to keep growers abreast of developments, so that farm management changes could be made as soon as pertinent information became availabl e. 3

6 MATERIALS AND METHODS Two acres were used in the trials, with approximately one acre for cultivar and selection evaluations and th e other for cultural practices. Soil preparation included subsoiling, plowing, harrowing, and broadcasting of 2000 pounds lime per acre. Lime was added to the soil because ph 4.7 was considered less than minimum for the optimum growth and production of papayas. Wild sugarcane (Saccharum hybrid clone 'Moentai'), ironwood (Casuarina equestifolia), and brush box (Tristania conferta) were planted around the perimeter to provide wind protection against strong tradewinds and rainy weather, which, when occurring at the same time, could cause uprooting of the papaya trees. Drip irrigation was installed, and microtubes of inch diam et er were used as emitters to deliver the water from 1 2-inch plastic lateral lines. Seeds were planted in 3-inch peat pots. Two papaya seedlings were transplanted into each hole. The double-row system of spacing of plants was used. Toxaphene bait at 90 pounds per acre was applied for cu tworm control. Four months after transplanting, the sex of the trees was determined and one tree was allowed to grow at each hole. Each double row consisted of 40 or more plants. The soil was not fumigated for nematode control although soil test samples showed the presence of Helicotylenchus (spiral) and Rotylendulus (reniform) nematodes. Meloidogyne (root-knot) and Pratylenchus (lesion) type nematodes were absent. PART A-EVALUATION AND SELECTION The line evaluations consisted of 9 Hawaii Agricultural Experiment Station (HAES) inbred advanced lines and I grower line. The inbred advanced lines were 'Higgins', 'Wilder', and lines 26, 34,37,40,93,96, and 116; the grower line was 'Kapoho' Solo. Studies on. selection of individual trees showing adaptability and commercial characteristics were conducted with the following segregating populations: 197?, 108F 2' 11OF2' 181 S2 ' 233 be, and 234bc. Traits evaluated in the linetesting phase included average fruit weight; average percent total soluble solids; flesh color and firmness; average number of fruits per tree and average pounds of fruits per tree; uniformity of fruit size and shape; degree of carpellody or sterility; and Phytoph thora root rot tolerance. 4

7 Factors evaluated in the segregating lines were the same as those in the inbred line trials but more general in nature, and detailed data were not recorded. Seeds were sown on January 21,1975, and field transplanted in May There were 4 replications with 8 trees per replication in the inbred line evaluations. The segregating line selection consisted of 8 lines with 50 trees per line. Results and Discussion Of the 9 inbred advanced lines tested, 'Higgins' and HAES 26F6 compared favorably with 'Kapoho' Solo in fruit size and shape, firmness, and production tendency. Table 1 lists the characteristics and performance of each of the lines tested. 'Higgins' showed a multiplefruiting tendency. Although its yields were high, percent of the fruits were less than minimum in weight. Subtracting 20 percent of the fruit weight from estimated production, per-acre yield of 'Higgins' was still higher than the grower line, 'Kapoho' Solo. HAES 26F6 also showed promise as a commercial line, with smooth, well-shaped, uniform fruits; however, the relatively low percent total of soluble solids was unexpected, because refractometer readings taken at the Waimanalo Branch Station on the Island of Oahu have shown percent. Higgins and 26F6 showed some resistance to powdery mildew. Seeds of these 2 advanced lines tested were recommended for trial plantings by growers. Ten selections were made from segregating lines I 07F2 (l selection); 108F 2 (4 selections), 174F 3 (3 selections), and 234bc (2 selections). A short description of each selection is listed below: F 2 (R2-H21) smooth, l-lb fruits ; good production; best overall performance in this population F 2 (R4-HI8) smooth, 14- to 16-oz fruits; less compaction than others F 2 (R5-K25) smooth, 15-oz fruits; good fruit set but somewhat compacted due to multiple fruiting. May produce selections with less compaction in next generation. 5

8 Table 1. Tree and fruit characteristi cs of 9 inbred advanced lines and the Kauai selection of 'Kapoho' Solo planted by growers Average Average Average Average Estimated fruit weight soluble solids number fruits yield per tree total yield Lines (lb) (%) Flesh color per tree'' (lb fruit) (lb fruitacre)b 'Higgins' orange ,489 'Wilder' orange ,661 'Kapoho' orange ,978 26F ligh t orange ,836 34F orange ,653 37F light orange ,225 40F orange ,648 93F orange ,514 96S light orange , S pink ,596 0 a Average of 4 repli cati on s; fruit count includ ed all fruits. besti mates based on 691 trees per acre (spacing 7 X 7 X II ft ) from approximately 1-76 to 5-77.

9 4. 108F 2 (R6-H28) 16- to 22-oz fruits; smooth, slight compaction F2 (R6- K28) l5-oz fruits; smooth, some compaction. NOTE: The last 2 selections in 108F 2 seem to be the best trees in this population. Fruits are very smooth and firm even upon coloring. 6. l74f3 (R 10-H25) smooth, 14- to l6-oz fruits; good production. 7. l74f 3 (Rll-K16) smooth, 16- to 20-oz fruits; very productive, firm; low carpellody and sterility F3 (R 11-K25) 15- to l8-oz fruits; very productive, vigorous tree bc (RI5-H6) 14- to l8-oz fruits; slightly ridged; tree has short, obliquely upright leaf petioles bc (RI5-Hll) 14- to l6-oz fruits ; fruits slightly ridged; short, obliquely upright petiole. NOTE: 234bc is an attempt to produce a short, upright-petiole type of tree to increase number of trees per acre without reducing production and fruit quality. Other lines were eliminated for various reasons such as high carpellody or high sterility; large fruits; compaction; and soft fruits. Line 233bc was completely eliminated because many trees produced fruits that tasted bitter. Self-pollinated seeds were obtained from all selections to produce the next generation for evaluation. Important factors to consider in the development of new cultivars for the export markets are: (l) tolerance to the standard disinfestation treatment, and (2) shelf life. Disinfestation consists of submersion of fruits in F water for 20 minutes followed by cooling in water for 20 minutes and then fumigating with ethylene dibromide at the rate of 12 lbl 000 cubic feet of fumigation chamber space for 2 hours at ambient temperatures. Papaya lines that showed promise were subjected to disinfestation treatment and then stored at 55 F for 6 days to simulate shipping storage conditions. Presented in Table 2 are observations, after storage at room temperature, of two shipments that showed that the shelf life of promising papaya lines in the Moloaa Project was similar to shelf life in other areas of production and with other varieties tested. 7

10 Table 2. Tolerance of selections made to disinfestation treatment and shelf life Cultivar Initial Number Average or surface color of salable days selection (%) Storage fruits at room temperature 26F Stored 6 days at F and removed to room temperature storage 'Higgins' a 'Kapoho ' 'Waimanalo' b athe advanced degree of rip en ess of ' Higgins ' at the initial sta ge has probably contributed to its lower number of salab le days. b A significa n t obse rvatio n noted wa s th e susce ptibility o f 'Waimanalo' to sto rage decay ca used by Rhiz op us a nd anthrac nose. Table 3. Effects of spacing and irrigation levels on trunk diameter, tree height, and fruit count per tree (August 11, ctober 6, 1977) Trunk diameter Tree height Fruit Treatment (inches) (feet) counttree'' Spacin g 6 X 6 X 11 feet (854 plants) Low irrigati on b High irrigation? Average Spacing 8 X 6 X 11 feet (640 plants) Low irrigation!' High irrigation" Average a Harv est peri od Oct ober Mar ch bapproximat ely 3 galday. c Approximately 6 gal day. Note : Irrigation level not co nsiste nt becau se of pressure differences due to amount of water available in sto rage tank. 8

11 PART B-CULTURAL DEMONSTRATIONS The cultural trial was divided into two blocks. Block I consisted of factors involving fertilization, spacing, and irrigation. Generally, treatments for these factors were comparisons between the recommended practice and general farmers' practice. Data were taken from October 1976 to December Seeds were planted on August II, 1975, and transplanted into the orchard on October 30, In addition to soil preparation as discussed earlier, 1 po und of treble superphosphate was mixed with the soil at th e bottom of each hole ju st before transplanting and irrigation. Planting and field preparation procedures of Block II were the same as those of Block I; however, trees were planted later. Treatment groups consisted of 20 or more trees. Treatments were suggested by papaya growers, agricultural business agents, and University of Hawaii personnel. Th e treatments included mulching, soil fumigation, "Jorgen" nutritional mushroom foliar spray, planting techniques, and fertilization methods. Block I-Results and Discussion The results of spacing, irrigation, and fertilization tests in Block I indicate that with good cultural practices and management, papaya production is feasible at Moloaa. The estimated total yield obtainable is competitive with principal papaya-producing areas in the State. Effec ts of Spac ing and Irrigat ion Levels on Tree Characters Trees that were spaced 8 X 6 X 11 feet were more productive and larger in trunk diameter than those planted a1'6 X 6 X II feet (Table 3). At 6 gallons per day the differences in trunk diameter, tree height, and fruit count per tree between the two planting distances decreased (Table 3). This seems to indicate that the closer spacing of 6 X 6 X II feet is still sufficient for normal growth if there is adequate moisture. Effects of Spacing and Irrigat ion Levels on Average Fru it Weight The results in Table 4 did not provide sufficient evidence to support the beli ef that close spacing will reduce fruit size as this was not apparent in the spacings used. Fruit weight was not significantly affected by the difference in irrigation levels, indicating that the irrigati on leve ls were not wide enough to ca use differences either at the high - or low-density planting. 9

12 Treatment Date and fruit weight (in pounds) Spacing 6 X 6 X 11 feet (854 plantsacre) Avg. Wt. Low irrigation High Irrigation Average Spacing 8 X 6 X 11 feet (640 plantsacre) Low irrigation High irrigation Average o Table 4. Effects of spacing and irrigation levels on average fruit weight

13 Effects of Spacing and Irrigation Levels on Percent Total Soluble Solids Dat a in Tabl e 5 see m inco nsisten t and possi bly indi cat e sampling err or, but th ey do support experime nta l work carried on at Prin cess Orchards at Pulehu, Island of Maui, that indicated th at total soluble solids are not affected by differences in irrigation rates. On the other hand, the data show that the sugar levels tend to increase from May to November, with a po ssible decline setting in during Dec ember. Plant spacing did not seem to affect the perc ent total soluble solids du ring the 8-month period. Effects of Fertilizer Treatments with Two Lime Levels on Fruit Count As shown in Table 6, the highest fruit count in both lime plo ts was obtained in treatment F l ' with 2 pounds of trebl e supe rphospha te placed at the bottom of the planting hole and pound permonth until flow ering, followed by.75 pound of broadc ast on th e soil surface bimon thly. Sim ilar to papaya research carried on in in Pun a, Island of Haw aii, th e grea tes t response wit h phosphorus was in the initial fruit count in relation to th e amount of phosphorus applied. Thereafter, th e fruit count rem ained relati vely the sam e, with treatments having 2 or 4 pounds of trebl e superphospha te. Doubling the amount of trebl e supe rphosphate (trea tme nt F4) was not as effective as the 2 pounds of treble superphospha te used in treatment F l ' possibly because of initial toxicity to th e trees. All fertilizer tre atments that had th e fertilizer inject ed in to th e irrigation syste m bore less fruit in th e initial fruit count than those th at had th e fertilizer bro ad cast ed. However, fru it co unts tak en at late r dates seem to indi cate that fertilization through th e irrigation system was just as effective as broadcasting. Interaction of Spacing, Fertilizer, Lime, and Irrigation Treatment 11 (Ta ble 7), whi ch consists of 2000 pounds of lime per acre, 6 gallons of irrigation wat er per day, 2 pounds o f tre ble superphosphate at tim e of planting followed by broadcasting of.75 lb of every 8 weeks afte r flow ering, and spaced at 8 X 6 X 11 feet, was found to be most effec tive in obtaining th e highest fruit count, with 270 fruits per tree for the 17-month period. However, treatment 9 with 236 fruits per tre e at clos er tr ee spa cing was calculated to yield 201,96 2 fru its, or 2 8,962 more fruits, within th e 11

14 Treatment May June July Aug. Sept. Oct Nov. Dec. Average Spacin g 6 X 6 X 11 feet Low irrigation High irrigation Average Spacin g 8 X 6 X 11 feet Low irrigation High irrigati on Average N Table 5. Effects of spacing and irrigat ion levels on percent total soluble solids Percent total soluble solids Months, 1977

15 Table 6. Effects of fertilizer treatments under two lime levels on fruit count per tree at a spacing of 6 X 6 X 11 feet and irrigated at the rate of 3 gallons per day Number of fruits per tree a Per tr ee Per Treatment total acreyear High-lime plots (4000 Ibacre) F 1 (2 1b treble superphospha te; Ib mon th until flowering; broadc ast.75 Ibt ree8 weeks ) ,269 F2 (l lb treble superphosphate and 1 lb at planting; Ib treemonth injected) ,702 F3 (2 Ib treble superphosphate and 1 Ib at planti ng; ib t reem on th injecte d) ,294 F4 (4 lb treble superphosphate ; Ib m onth until flowering; broadcast.75ibtree8 weeks ) ,223 F5 (2 lb treble superp hosphate; inject ed.62 lbs weeks) ,202 Low-lime plots (200 0 lbacre) F ,140 F ,874 F ,0 29 F ,787 F S , w athe number of fruits was obtained by averaging fru its per tree for 17 months. Youn g fruits counted on would mature approximately S months later.

16 a l l 1.5 gal2 days; increased to 3 galday at flowering gal2 days; increased to 6 galday at flowering. F1 Fe rtilization 2 Ib tre ble superphosp hate in ho le and bro adcast.20 Ib of month and increased up to.75 Ibt ree8 weeks at or befo re floweri ng. F 2 lib treble supe rphosphate in hole and broadcast lib un til 3 months. Thereafter injec t.15 Ib of tr eemonth in irrigation water. SI Spacing 6 X 6 X 11 feet (854 plant sacre). S2 Spacing 8 X 8 X 11 feet (640 plantsacre). L lb limeacre broadcast before planting. L lb limeacre broadcast before planting. bthe number of fruits per tree is for a period of 17 months since youngest fruits cou nted will matu re approximately 5 mo nths lat er......j:::a. Table 7. Effects of spacing, fertilizer, lime levels, and irrigation on fruit count Fruit count No Treatrnent'' per tree b per acreyear II F2SI LI ,890 II F2SI L ,257 II F2S2L I ,576 II F 2S2L ,580 IIFISILI ,202 I I F lsi L ,078 II F I S2LI ,217 I I F IS2L ,168 I2F I SI L I ,561 I 2F ISI L , F I S 2 L I ,130 I2F I S2L ,390 I 2F2S 1 L I ,023 I 2F2SIL , F 2 S 2 L I ,164 I2F2S2L ,585

17 same period. This is a difference of approximately 16.7 percent in productivity per acre. On a yearly basis, the fruit count is 142,561 for treatment 9 as compared with 122,130 for treatment 11. Data on spacing from Table 4 show that the closer spacing in the trial did not reduce fruit size. Small or undersized fruits could be a marketing problem if reduced fruit size did result from closer spacing. Based on the 1977 average wholesale price of 12 cents per pound, this means that with the closer spacing in treatment 9 as compared to the spacing in treatment 11, there would be $1737 more income per acre if only 50 percent of the fruit were marketed from the date of harvest, October 14, 1976, to March 6, 1978, a period of almost 17 months. Irrigation is a major cost factor in papaya production at Moloaa. Treatments 5 and 9 (Table 7) are the same except for irrigation rates, which are 3 and 6 gallons of water per day, respectively. On the basis of agriculture water rates of July 1, 1978, the cost of irrigation of these two treatments at 36 cents per 1000 gallon is $.005 per fruit (I-1b average) and $0.009 per fruit, respectively, based on 50 percent marketable fruits. Calculations below are figured on a per-acre basis for 17 mon ths: Treatment 5: 3 galtree X 480 days ' 1440 gal X 854 treesacre $ gal water $ ,810 2 Treatment 9: 6 galtree X 480 days 2880 gal X 854 treesacre ,981 1b Irrigation Costs 181,620 fruits per 17 months' yield 1440 gal watertree 1,229,760 gal water $245.95acre.003fruit 201,961 per 17 months' yield 2880 gal watertree $ fruit At the average wholesale farm price of marketable fruits of 12 cents per pound, and with fruits weighing approximately 1 pound each, the monthly net gain with treatment 9 over treatment 5 with 50 percent marketable fruits is $60.91 per acre per month. However, this does not take into consideration the extra cost of water used -to grow the trees before harvesting in treatment 9. 1Irrigation for 16 months with i month of adequate rainfall. 250 percent marketable fruit. 15

18 Table 8. Effects of mulch, fumigation, and propagation methods on trunk diameter, tree height, fruit count, total soluble solids, and average fruit weight Treatments Total Trunk Tree soluble Average Fumigation diameter height Fruit solids fruit weight Mulch galsacre BBC Propagation (inchesj'' (feet)a count b (%)C (poundsj'' Bagasse" 0 Transplanted Wood shavings" 0 Transplanted Aluminum painted plastic 0 Transplanted Black plastic 2 Seeded Black plastic 0 Seeded Black plastic 4 Transplanted Black plastic 0 Transplant ed Black plastic 2 Transplanted ameasurements taken bharvest period to caverage of 11 sampling periods through harvesting season. d'kapoho' Solo. All oth ers 'Waimanalo'.

19 Block II-Results and Discussion Effects of Mulch, Fumigation, and Propagation Methods on Tree Characters Effec ts of the mulch, fumigation, an d prop agation tr eatm ents are presented in Table 8. Th e larg est trees an d the highest fruit co un t resulted from th e bagasse mulch treatment, and th e lowest fruit count from th e wood shavings mulch. Th e BBC fumigation treatments did not produce consiste n t results. For th e direct-seed ed plots, th e BBC fumigation treatments produced larger plants and more fruits. However, for th e tran splanted plots, th e 2-gallon-pe r-ac re-ra te tr eatm ent produced sma ller plants with few er frui ts than did no fumigation, whil e th e 4-gallon-per- acre-rat e trea tm ent produced better plants and more fruits. Th e direct-seed ed plots an d th e tran splanted plots were planted in th e field on th e same day. Thus th e dir ect-seed ed pl ants were mu ch younger than th e transplanted plants, and thi s is refl ect ed in smaller trunk diameter an d sho rte r tree height. However, the direct-seed ed plots had more fruits than the transplanted plots. Effects of "Jorgen" on Fruit Set and Total Soluble Solids Th e results of th e " Jorgen" treatments on th e papaya cultivar 'Waima nalo' (Table 9) do not show any advan tage over the nontreated cantrols. Table 9. Effects of "Jorgen" on papaya cultivar 'Waimanalo' at Moloaa sprayed at 3,5, and 7 months Trunk Tree Total Average "Jorgen" diam eter height Fruit soluble solids fruit weight treatment (inchesj'' (feet)a count b (%)C (pounds)c ppm ppm am eas urcrnents taken bh a rvcst pe riod to cavera ge of 12 sa m pling peri od s thro ugh ha rves t ing period. 17

20 Table 10. Effects of methods of fertilizer application on trunk diameter, tree height, fruit count, total soluble solids, and average fruit weight Treatment Trunk diameter (inchesj'' Tree height (feet)a Fruit countb Total soluble solids (%)C Average fruit weight (poundsj'' Dry only (preplant 2 lb rsr",.25 lb of per month for 6 months; then.75 lb of per 8 weeks) Dry and liquid (preplant 2 lb TSP;.25 lb of per month for 6 months; then 1.33 lb of liquid per 8 weeks) TSP and liquid (preplant 2 lb TSP;.44lb of liquid per month for 6 months; then 1.33 lb of liquid per 8 weeks) Liquid only (.5 lb of liquid per month for 5 months; then 1.5 lb of liquid per 8 weeks for 6 months; then 1.33 lb of liquid per 8 weeks) ameasurements taken bharvest period to c Average of 5 sampling periods through harve sting period. dtreble superphosphate.

21 Effects of Dry (F 1 Table 6) and Liquid Fertilizer Combinations The four methods of fertilizer ap plication are presen ted in Table I O. Although the actual amounts of fertilizer were different ini tially, at the eigh th month th e total amoun ts were qu ite similar. Th e t reatm ent that com bin ed dry and liquid formulations produced larger plants and th e high est fruit count. Th e treatment that used only liquid form ulations produced the lowest fruit count as well as th e low est percentage o f total soluble so lids. It should also be pointed out th at th e liquid formulation treatment had the lowest initial amount of phosphorus. SUMMARY AND CONCLUSIONS If Moloaa is to make an y advances in improving it s stra ins in papaya produ ction, it will be necessar y to h ave more time for varietal evaluations of the grower lines as well as of those lines from th e College of Tropical Agriculture and Human Resources. HAES 26F6 ' and 'Higgin s', as well as a few selected individuals from segregating lines, show considerable promise. Th e effects of cultural practices at Molo aa were initiat ed and st udied with a limited objective in mind becaus e of e con omic constraints. How ever, the results show that papaya production is feasibl e at Molo aa with the proper combination of cultural practices. The results of th e trials sh ow that, with good management and cultural practices, papay as can be a viable commercial crop at Molo aa, Island of Kauai, on forme r sugarcane and pineapple land. Th e cultural recommendations presented here are based on the information obtained from Moloaa as well as from expe riences obtain ed elsewhere within th e State of Haw aii. We ex pect th at these recommendations will be am ended to meet individual sit uations an d as new information becomes available. 19

22 CULTURAL RECOMMENDATIONS It is assumed that normal or chard practices such as field preparation as described and disease, insect, and weed control are being carried on. Th e following cultural recommendations will be effective only as other orchard practi ces are accomplishe d. I pounds of lime per acre. 2. Approximately 3 gallons of water per tree per day during the rai ny season and up to 6 to 8 gallons during dry periods. 3. (a) 2 pounds of treble superphosphate pla ced at bottom of planting hole and.20 pound of per month until flowering. Thereafter,.75 pound of fertilizer broadcast every 2 months. OR (b) A combination of dry and liquid preplant application of 2 pounds of treble superphosphate and.25 pound of per month for 6 months then 1.33 pounds of liquid fertilizer injected through the irrigation system th ereafter on ce per 8 weeks. Increase fertilization, if found necessary by visual ob serv ation andor plant tissue analysis. 4. Spacing 6 X 6 X II feet. DISCLAIMER Th e use of brand nam es in this publication is for conveni en ce and do es not imply endorseme nt of the products or th e manufacturers by the College of Tropical Agriculture and Human Resources or the United States Departm ent of Agriculture to the ex clusion of othe r products that may be suitab le. 20

23 ' (.--1 I '. j ' I 1, t.. ~ ' -I. ) Hawai'i residents may order single copies :01" this.pu b lica tion free of charge from county Cooperative Extension Service offices. Bulk -orders or out-of-state inquiries should be sent to the Agricultural Publications Distribution Office, College of Tropical Agriculture and Human Resources, University of Hawai'i at Manoa, 2500 Dole Street, Kraussl21, Honolulu, Hawai'i Price " per copy to bulk users, $0.70 plus postage. I I I )

24 . - ) I. I ; ' I ' I Issued in furtherance of Cooperative Extension Work, Acts of May 8and June 30, 1914, in cooperation with U. S. Department of Agriculture, and Interim Dean and Director Roy K Nishi- - moto, Cooperative Extension Service, College of-tropical Agriculture and Human-Resources, University of Hawai'i at Manoa, Honolulu, Hawai'i An Equal Opportunity Employer providing programs and services to the citizens of Hawai'i without regard to 'race, color, national origin, sex, religion, age, disability, political beliefs, and marital or familial status. (' I CIRCULAR 497-March 1980 (Reprinted 1295, 1.5M),