Genetics of sterility behaviour in Thermo Sensitive Genic Male Sterility system in rice (Oryza sativa L. )

Abstract

A total of 1493 F2 populations of five crosses were evaluated to study the TGMS nature under high temperature regime at Coimbatore. The present study revealed that the observed variation among 1493 F2 populations showed 25 per cent of population were completely sterile. The chi-square analysis did not yield significant outcomes for the crosses TNAU 45 S x CB15127, TNAU 60 S x CBSN 17, TNSAU 60 S x CBSN 20, and TNAU 95 S x CBSN 366. The expected segregation ratio of 75:25 (fertile: sterile) was not significant (P>0.05) in crosses viz., TNAU 45 S x CB15127, TNAU 60 S x CBSN 17, TNAU 60 S x CBSN 20 and TNAU 95 S x CBSN 366 indicating that the observed ratio was a goodfit. Stigma length, stigma breadth, anther length, and glume opening angle showed positive skewness and platykurtic distributions, suggesting that the genes were under the influence of dominant x dominant-based complementary gene behaviour and controlled by a larger number of genes. However, stigma exsertion, anther breadth, sterile lemma length, panicle length, and panicle exsertion exhibited negative skewness and leptokurtosis distribution patterns, suggesting gene regulation by a smaller number of genes.

Keywords

• frequency-density curve
• rice tgms
• chi-square
• skewness and kurtosis