Thumbnail Image

Theses

Browse

19862
Reset filters
Subject: Plant Breeding × Author: KAU × Author: Sreekumar, S G × End date: 1999 × Start date: 1980 × Type: Thesis ×
Reset filters

Search Results

Now showing 1 - 2 of 2
  • Thumbnail Image
    ThesisItemOpen Access
    Genetic variability, path analysis and stability parameters in sugarcane
    (Department of Plant Breeding, College of Agriculture, Vellayani, 1986) Sreekumar, S G; KAU; Gopinathan Nair, V
    Investigations on genetic variability, path analysis and stability parameters wore conducted at the Sugarcane Research Station, Thiruvalla, Sugarcane Research Centre, Chittoor and Horticultural Research Station, Ambalavayal. The analysis of data collected from 48 clones evaluated at Thiruvalla revealed that the clones showed significant differences for all the 21 characters except Juiciness at 10th month in the first ratoon crop. The germination count on the 45th day, shoot count on the 180th day, number of late shoots at harvest, number of millable canes per plot, cane yield per plot and sugar yield per plot recorded moderate to high heritabiiity in the broad sense coupled with high genetic advance both in the plant and in the first ratoon crops indicating that selection based on these characters will be effective in improving cane and sugar yields. Correlation studies revealed that cane yield per plot had significant positive genotypic correlations with germination count on the 43th day, shoot count on the 180th day, number of millable canes per plot, cane weight and length of cane both in the plant and the first ratoon crops. Therefore, improvement in any one or more of these characters will result In a simultaneous improvement in the yiold of cane. Tho quality characters such as Juiciness, brix, pol and C.C.S. percentages at 12th month had positive but non-significant correlations with cane yield In ths plant crop and the first ratoon crop, suggesting difficulty in the simultaneous improvement of cane yield and quality characters through direct selection. The number of late shoots at harvest had highly significant positive genotypic and phenotypic correlations with the yield of cane in the first ratoon crop indicating that the number of late shoots at the time of harvest can be considered as a reliable criterion for the selection of clones with good yielding ability in the ratoon crop. Sugar yield recorded significant positive gonotypic correlations with cane yield and tho components of cane yield such as germination count on the 45th day, number of millable canes per plot, cane weight and length of cane. Sugar yiola also had significant positive genotypic correlations with brix, pol and C.C.S,percentages at 12th month, Tho significant positive gonotypic correlations of sugar yield with cane yield and its important components suggests that by increasing the cane yield, sugar yield per plot can be increased.
  • Thumbnail Image
    ThesisItemOpen Access
    Genetic variability, path analysis and stability parameters in sugarcane
    (Department of Plant Breeding, College of Agriculture, Vellayani, 1986) Sreekumar, S G; KAU; Gopinathan, Nair V
    The stability analysis done for component characters on cane yield and sugar yield gave an insight in to the characters contributing to yield stability across environments. Among the cane yield and its most important components viz. number of millable canes per plot and girth of cane the absence of G x E interaction itself is an indication that these characters are stable across environments. The other components of cane yield such as cane weight and length of cane had significant linear components of G x E interaction alone suggesting the stability of these characters. In sugar yield and its more important components viz. brix and pol percentage, the pooled deviations were highly significant suggesting the unpredictability and unstable nature of these quality characters across environments. Therefore, for breeding stable varieties across environments due weightage must be given for characters like number of millable canes per plot, cane weight, girth of cane and cane yield per plot.