Fl heterosis over midparent (MP) and better parent (BP) and F2 inbreeding depression (ID)
were studied in 8 crosses of rice for grain yield/plant and its four other component traits,
Le., plant height, effective tillers/plant, No. of filled grains/panicle and lOOO-grain weight.
Highly significant and positive MP and BP heterosis for grain yield was expressed by four
hybrids and ID in each case invariably accompanied in F2. Such high heterosis for yield
was due to additive heterotic effect of one or more component traits. In all the cases,
heterosis for effective tillering was found to be the major contributor and number of filled
grains/panicle contributed less to grain yield heterosis. High heterosis accompanied by
high ID for effective tillers/plantand number offilled grains/panicle indicated the presence
of nonadditive gene effects governing the inheritance of these traits. Since growth vigour
was not of retentive nature as indicated by high ID in F2 for grain yield, it should be
exploited in Fl itself.
Keywords: Heterosis, inbreeding depression, rice, Oryza sativa.
Article DOI: NA
Print ISSN: 0019-5200
Online ISSN: 0975-6906
C. D. R. REDDY AND Y. S. NERKAR info_circle