Morpho-Physiological and Yield Variability Assessment Among indica Rice Lines.

Rice (Oryza sativa L.) is one of the most important food crops in the world that is consumed by more than 3 billion people mainly as a staple food. However, the world’s population is rapidly increasing and is projected to grow from seven to nine billion by 2050. Therefore, screening rice lines for early maturity and high yield are the two key factors to enhance rice production. In this study, 74 rice genotypes, mostly Indica, were screened for maturity, morphology, physiology, and yield traits. Genotypes were then evaluated and clustered into different vigor, maturity and yield groups. Eleven cultivars were classified as early maturing cultivars with less than 100 days to flowering (DF) including IR08A172 that was the earliest-maturing genotype. Six cultivars were classified as late maturing with more than 140 DF, with IR65600-81-5-2-3 being very late maturing genotype with 153 DF. Most of the cultivars were classified in the moderate maturing group with 100 to 130 DF. Similarly, ten cultivars were classified as high yielding including IR08A172 that had the highest number of panicles and grains per plant. Seven cultivars were classified as low yielding, with IR93324 having the least number of panicles and grains per plant. Based on the results of individual and cumulative vigor response indices, 60 and 9% of the genotypes showed high and very high vigor response indices, respectively while 20 and 11% of the genotypes showed moderate and low and very low vigor response indices, respectively, among the 74 rice genotypes tested. Overall, huge variability was observed among the selected rice genotypes for vigor, maturity and yield. This variation could be useful to rice breeders to develop new improved varieties in their breeding programs.