Date of Award

1986

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Abstract

Heritability and other genetic effects for the date of first flowering, date of maximum flowering, average flowering date, percent flowering, pith and brix in sugarcane were estimated in a diallel cross experiment. A three year study indicated that the date of first flowering, date of maximum flowering, average flowering date, and percent flowering were highly heritable characters. The heritability estimates of pith and brix were very low and variable. Partitioning of total direct response in parental lines into average direct and average maternal genetic effects indicated that average maternal genetic effects of the early and late lines were larger in magnitude for all the characters studied. Maternal effects of the early line resulted in earlier dates of first flowering, maximum flowering, average flowering and an increase of percent flowering, while maternal effects of the late line delayed these dates and decreased percent flowering. Maternal effects of the early line increased the incidence of pithiness, while that of mid and late lines decreased it. Maternal effects of the early line decreased brix, while that of the late line increased it. Correlation studies indicated that the date of first flowering, date of maximum flowering and average flowering date were similar in nature and were probably controlled by the same set of genes. Increase in percent flowering and pith resulted in a decrease of brix. With such information at hand, a breeder can easily identify parental lines suitable as male or female for superiority of traits known to be determined by the individual genotype or maternal effects respectively.

Pages

103

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