Salinity stress is one of the major environmental constraints limiting rice production worldwide, particularly in
arid and semi-arid regions where water quality and soil salinization continue to worsen. Developing rice genotypes
with improved salinity tolerance is essential for sustaining productivity in affected areas. In this study, seven rice
parental genotypes and their 21 F₁ crosses, developed through a half-diallel mating design, were evaluated under
normal irrigation and salinity stress to investigate heterosis, general combining ability (GCA), and specific
combining ability (SCA) for key agronomic traits. The traits studied included days to 50% heading, number of
panicles per plant, panicle length, panicle weight, 100-grain weight, and grain yield per plant. The analysis of
variance revealed highly significant differences among genotypes, parents, crosses, and parents versus crosses for
most traits under both conditions, reflecting substantial genetic variability. GCA and SCA mean squares were found
to be significant for all studied traits. Several parents, particularly P3, P4, P5, and P6, were identified as good
general combiners for earliness, yield, and their components. In addition, crosses such as P3 × P6, P1 × P6, P5 × P6,
and P2 × P5 showed desirable heterotic effects under salinity stress, highlighting their potential for developing highyielding, salt-tolerant rice hybrids. The results emphasize the effectiveness of half-diallel analysis in identifying
superior parents and cross combinations for breeding programs aimed at improving salinity tolerance and yield
stability in rice. |
