COMBINING ABILITY AND HETEROSIS FOR AGRONOMIC AND YIELD TRAITS IN EGYPTIAN TWO-LINE HYBRIDS OF RICE (Oryza sativa L.) INVOLVING PHOTO-THERMO SENSITIVE GENIC MALE STERILE LINES

doi:10.12816/ejpb.2024.352183

COMBINING ABILITY AND HETEROSIS FOR AGRONOMIC AND YIELD TRAITS IN EGYPTIAN TWO-LINE HYBRIDS OF RICE (Oryza sativa L.) INVOLVING PHOTO-THERMO SENSITIVE GENIC MALE STERILE LINES

Document Type : Original research

10.12816/ejpb.2024.352183

Abstract

Hybrid rice is an important technical innovation in hybrid rice seed production based on photo-thermo-sensitive genic male sterile (PTGMS) lines in rice. The present study was undertaken to investigate the magnitude of genotypic variation, both general and specific combining abilities, and estimate the genetic behavior. The study also aimed to assess the potentiality of heterosis expression for new developed photo-thermo-sensitive genic male sterile lines (PTGMS) and six exotic and novel Egyptian testers of new plant types using line x tester analysis for agronomic and yield traits to get useful information for two line system hybrid rice in Egypt. Highly significant differences for GCA effects among PTGMS lines and testers for all studied traits. Highly significant differences for SCA effects for all the studied traits. PTGMS-78 was the best general combiner among sterile lines followed by PTGMS-38, while the EJGSR 182 was the best general combiner among the restorer lines followed by Sakha Super 303 then Sakha Super 301. The higher GCA effects of parents exhibited stronger and superior heterosis in hybrids. Hereitability estimates in narrow sense (h²_n) were high for all traits studied. Nine and five hybrid rice combinations gave significant and positive estimates of SCA effects for grain yield plant^-1 and grain yield t/ha^-1, respectively. The best SCA effects were obtained for the combinations, PTGMS-43xEJGSR-182, PTGMS-23xSakha Super 303, PTGMS-38xSakha Super 303, PTGMS-20xEJGSR -182, PTGMS-78xEJGSR-182 and PTGMS-20xMinghui 63. Among 30 super hybrid combinations, 11 were the most promising with mean performance of grain yield ranging from 14.82 t/ha^-1 for PTGMS-78 x EJGSR-182 to 14.22 t/ha^-1 for PTGMS-38 x Sakha Super 303 with superiority to the standard check variety ranging from 36.97% to 31.42%.

Keywords