No abstract

The present study was conducted to evaluate the genotypes having Sub1 gene under submergence and drought stress in field conditions at Nuclear Institute for Agriculture and Biology (NIAB), Faisalabad. A pot experiment was also performed to study the influence of complete submergence on elongation and survival percentage of fiveSub1 genotypes along with two high yielding local cultivars. All Sub1 genotypes showed less elongation percentages than Super Basmati and KSK-133 while maximum survival percentage was observed in IR-07-F289 Sub1 followed by Swarna Sub1 and FR-13A. Five rice genotypes (FR-13A, Swarna Sub1, Ciherang Sub1, IR-07-F289 Sub1 and IR-44 Sub1) along with two high yielding local varieties (KSK-133 and Super Basmati) were evaluated under submergence stress in field conditions. The field experiments were laid out in split plot randomized complete block design (RCBD) with three replications. Results of ANOVA revealed that chlorophyll contents, plant height, number of productive tillers per plant, panicle length, total spikelets per panicle, number of grains per panicle and 1000 grain weight were affected by submergence stress. While in another experiment drought stress was applied for 30 days on five Sub1 genotypes along with Nagina-22 (Drought tolerant check) and IR-64 (drought susceptible check) in split plot design with three replications. Drought stress severely reduced all the parameters under study except leaf area, number of productive tillers per plant and biological yield per plant which remain unaffected. Overall results revealed FR-13A only produced grains under submergence stress while under normal and drought conditions it did not produced grains. All Sub1 genotypes performed well under submergence stress. Swarna Sub1 significantly produced more primary branches per panicle (10.5), yield (5.13 g) and harvest index (13.09) under drought stress as compare to the Nagina-22. Whereas remaining all Sub1 genotypes also showed better performance than drought susceptible check (IR-64) and showed non-significant difference with Nagina-22 for most of the drought tolerance related traits. The results suggested that genotype having Sub1 genes can effectively be grown under rainfed region which are equally prone to floods and drought stress.