Genetic architecture of cashew germplasm accessions

Abstract

The variability and genetic architecture was assessed deploying 13 important quantitative characters of 478 cashew germplasm
accessions evaluated and conserved in National Cashew Field Gene Bank, Directorate of Cashew Research, Puttur in India.
Considerable variability was observed for all characters and the highest co-efficient of variation (CV) was observed for sex ratio
followed by cumulative yield per plant and apple weight. The lowest CV was observed for shelling percentage followed by shell
thickness. Frequency distribution patterns showed highly positively skewed distribution for characters such as nut weight, sex
ratio, apple weight and apple to nut ratio. Genetically, it is evident that decreasing alleles are in excess and dominant for these
characters. Tree spread, kernel weight and cumulative yield per plant showed moderately positively skewed distribution indicating
decreasing alleles are in slight excess and dominant. Flowering intensity showed moderately negative skewed distribution indicating
the presence of increasing alleles in slight excess and their dominant nature. Tree height, shell thickness, flowering duration,
shelling percentage and leaf area showed approximately symmetric distribution indicating increasing and decreasing alleles are in
equal proportion and the dominance is ambi-directional. Significant positive correlations with cumulative yield per plant were
observed for tree height, tree spread, sex ratio, flowering duration, apple to nut ratio, shelling percentage and leaf area and
significant negative correlation for shell thickness. The present germplasm collection represents sufficient number of accessions
for both quantitative and qualitative characters in desired direction. However, based on the frequency distribution patterns, it is
imperative to collect germplasm with dwarfness, less tree spread, high nut weight, apple weight and high yield.