Study of variability, combining ability, genetics and association of different yield related traits in rice (Oryza sativa L.) genotypes

Rice is recognized worldwide as a primary staple food crop which provides calories approximately half of growing world population and the maintenance of its high productivity is of utmost importance in the context of global food security. The objective of this research was to examine the variability and correlation between yield-related characteristics in rice. A total of 15 F₁ crossings, in addition to five lines and three testers were subjected to evaluate in a Randomized Complete Block Design with three replications at the experimental site of the Department of Plant Breeding and Genetics, Faculty of Agriculture and Environment, Islamia University of Bahawalpur, Pakistan, during the year 2022–2023. Analysis of variance (ANOVA) showed that genotype revealed significant differences for most variables except grain length, days to maturity, panicle weight and grain yield per plant. The study found adequate spontaneous genetic diversity for rice yield parameters such as plant height, panicle length, grain per panicle, grain width, days to heading and spikelets per panicle. ANOVA also revealed significant differences among the studied traits in parents, crosses, lines, testers and their combinations. Combing ability revealed potential parents and hybrids for different studied parameters. Line 37651 had positive general combining ability (GCA) (8.888) effect for grain yield per plant and line 37481 reveled highest negative GCA among the lines (− 4.984). Tester 37500 showed significant positive GCA (4.072) effect for grain yield per plant while among the negative GCA (− 3.598) was exhibited by tester 37644. Cross 37651 × 7968 exhibited significant positive specific combining ability (SCA) (18.362) effect and among cross 37651 × 37500 showed significant negative SCA (− 13.18) effect for grain yield per plant. Grain yield per plant exhibited significant genotypic positive and negative correlation with various studied parameters. From the results it was found that diversified parents and best combiners (hybrids) may be useful in breeding high-yielding rice cultivars.