Title: Evaluation of adaptability and stability of promising salinity tolerant rice mutant lines in regional yield trials
Author: Allahyar Fallah
To achieve and introduce the top lines as suitable cultivars in the region in terms of performance stability in saline conditions, Yield, quality, and relative resistance to important pests and diseases of rice, 9 top lines were selected from the preliminary performance test of 2017, along with salinity tolerant cultivar (FL478) and Tarom Mahalli as the control in saline lands, a total of 11 treatments in a randomized complete block design with three replications, and Feridoonkanar and Bahnemir areas were evaluated during the crop years of 2018 and 2019 and in Khuzestan during the years of 2019 and 2020. A one-year experiment was conducted in the relatively salty field of the Shahneh Kalay Amol in 2020. The seeds of selected mutants were sown with the control in the station nursery of the Deputy of Rice Research Institute. Transplanting was done simultaneously on the mainland in two regions of Mazandaran. The size of the plots was 4 × 3 m2 and the seedlings were planted in hills of three to four plants with a density of 20 × 20 cm. Traits of the number of days up to 50% of flowering were recorded with regular visits to the field at the flowering stage. Plant height and number of panicles per hill at physiological maturity were measured by four hills. Other agronomic traits such as panicle length, number of filled and empty grains, and 1000-seed weight, by selecting five panicles at random for each mutant, and the replication and test location were calculated. The salinity of the experimental field varied between 5-8 and the salinity of irrigation water varied between 3-7 dS / m. The results of the combined analysis showed that the effect of genotype on the measured traits was significant at the level of 5 or 1% probability. The three mutants, 133, 2212, and 2310, had lower up to 50% flowering days than the Tarom Mahalli as the control. The rate of reduction of mutant plant height was 6-29% compared to Tarom Mahalli as the control. The number of panicles per hill among promising mutants varied between 15.3 – 19 in the hills and all mutants had more panicles per hill than the Tarom Mahalli as the control. All mutants had higher grain yield than Tarom Mahalli as a control but had lower grain yield than salinity tolerant as a control (FL478). Mutants 2310, 3121, and 221 had the highest yields in salinity stress, but the selected lines for the improved experiment were earlier in the field. The results of Khuzestan showed that in choosing the line or lines that tolerate salinity for the province, in addition to salinity stress, the role of heat stress and the interaction between them must be fully considered, Because the selected lines went to the panicles but no yield performance was achieved.
Keywords: Rice, Stability, Flowering, Yield, Selected Mutant