SELECTION INDICES FOR HIGH YIELD IN SUGARCANE

Transcription

1 Cane Breeding SELECTON NDCES FOR HGH YELD N SUGARCANE V.G. Dosado, R.E. Tapay and H.M. Miayo Philippine Sugar Commission La Carlota City, Philippines ABSTRACT Selection indices for high cane and sugar yields were determined from ten experiments for three cropping seasons. The zero order correlation coefficient and the coefficient of determination indicated that high sugar yield was primarily due to ton- Stalk weight and millable stalks per stool were closely associated with high tons cane per hectare and explained most of the variance in sugar yield among the tonnage yield components. The most stable and desirable index for selection for high tons cane and sugar yields was more millable stalks per stool. l NTRODUCTON Sugar yield and other economic traitsare controlled by many genes. As quantitative characters, they are easily influenced by changes in the' environment. For be exercised in picking out clones in the F1 population after hybridization so that selections are genetic rather than environmental The expression of a plant character may also be influenced by other traits. Quantitative estimates of these relationships may provide information useful in A more reliable selection criteria is necessary. The selection indices should not be only closely associated with high yield but it should also be easily distinguished visually, relatively stable among varieties and environmental conditions, and preferably pre-harvest characters. These selection indices could be obtained from my parent used in hybridization. According to Hebert4, stalk diameter, erectness of stalk, stalk per stool and brix of progeny could be predicted from the characteristics of the parents. 1104

2 1105 CANE BREEDNG Empig et a1.3 reported regressjon as 9 means of determining stability. f B = 0, it means that the genotype has little or no response to changing environment. The most desirable genotype is one with high mean and low "b" in tests in sevpral locations. n this study, the association of some characters with tonnage and the magnitude of their influence on sugar production were analyzed. The parameters of stability of these characters as tonnage and sugar yield components and the influence of other traits and varieties from ten experiments for three cropping seasons were evaluated. MATERALS AND METHODS Widely grown varieties differing in yield components were used. Phil 56226, high in picul sugar per ton cane (PS/TC) and medium in tonnage, and Phil 6007, high in tons cane per hectare (TC/Ha) and medium in sugar quality were planted 33 cm in rows one meter apart. The varieties were distributed at random in plots $ifs x five meters. The plots were fertilized wiih kilograms per hectare pf 1 nitrogen, phosphorous and potassium, respectively, at planting. All data were taken at harvest. The stalks in the inner three rows and of each plot were harvested for yield. Fifteen stalks selected at random from each plot were used for juice analysis. RESULTS AND DSCUSSON The Relationship of Cane Yield and Sugar Quality with other Plant Characteristics The varieties differed in their important sugar yield components. Phil was stable in sugar quality as indicated by low "b" and high mean. t produced, ggnificantly better PS/TC while Phil 6607 was outstanding in TC/Ha (~aplk' 1).. TABLE 1. Means and regression values of some plant characters of two ra0&@ mended sugarcane varieties f; 1, CHARACTERS MEAN 1/ Regression Values 2/ Phil Phil 6607 Phil Phil Stalk diameter (cm) 2.62 b 2.98 a 19.62" Stalk length (cm) b a 0.64" Millable stalk/stool 3.05 a 3.30 a 21.48" ** 4. Stalk weight (kg) 1.01 b 1.20 a ** 5. Picul sugar per ton cane 1.92 a 1.75 b Tons cane per hectare b a 46.30' * * * 7. P icu s sugar per hectare b a / Means with similar letters between varieties are not significant at HSD Values with in varieties with asterisks are significant at t 01.

3 V. G. DOSADO, R. E. TAPAY AND H. M. MAYO 1106 High degree of interdependence existed between diameter, length, weight and number of millable stalks per stool with tons cane per hectare (Fig. 1). These were indicated by positive correlation coefficients, all significantly different from zero at one per cent level. Stalk weight which is a function of 'tonnage was more influenced by stalk length (0.47"") than by stalk diameter (-0.08). Of these plant characters, stalk diameter (-0.40"") and stalk length (-0.44"") showed negative' and significant influence on sugar quality. The greater negative influence of stalk length could be attributed to the presence of high reducing sugars in the top parts of the stalk which tend to lower sugar quality. PSlHa -0.44** * FGURE 1. Relationship of sugar yield (PS/Ha) with sugar quality (PS/TC) and the components of cane yield (TCHa)

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6 stalk Coef..59 *.49 *.80* "29

7 V. G. DOSADO, R. E. TAPAY AND H. M. MAYO REFERENCES 1. Odsado, V.G., R.E. Tapay and H.M. Miayo (1978). Charac!ers associated with yield of sixteen sugarcane varieties. Paper read at the 26th Philsutech Annual Convention, PCC, Manila. 2. Empig, L.T. (1972). Sugarcane breeding philosophy for the Philippines. Proc. 20th Philsutech Annual Convention, Makati, Rizal. pp Empig, L.T., E.L. Lapastora, L. Cosico and B. Magajes (1976). Factors affecting stability of performance of sugarcane varieties. Paper read at the 24th Philsutech Annual Convention, lloilo City, Philippines. 4. Hebert, L.P. (1965). A brief review of genetics of sugarcane. Proc. nternational Society of Sugarcane Technologist. pp Rosario, E.L. (1977). Some behavior of the sugarcane plant in increasing efficiency in sugar production. Paper read at the 25th Philsutech Annual Convention, PCC, Manila, Philippines. NDCES DE SELECCON PARA ALTOS RENDMENTOS EN CARA DE AZUCAR V.G. Dosado, R.E. Tapay y H.M. Miayo RESUMEN Ee determinaron indices de seleccion a partir de 10 experimentos durante tres cosechas. El coefficiente de correlacion de orden car0 y el coefficiente de deteminacion indicaron que 10s altos rendhnientos de azucar se debieron primeramente a1 rendimiento agricola. El peso de 10s tallos y 10s tallos molibles por planton estuvieron asociados fuertemente con altas toneladas de caiia/hectarea y explicaron la mayor parte de la variacibn en re~ldimientos de aziicar entre las toneladas de 10s co~nponentes del rendimiento. El indice mas deseable y lnas estable, para la seleccion de altos rendimientos de azucar y de caaa fue tallos nlobible por planton.