SELECTION OF ONION (Allium cepa L.) GENOTYPES FOR DROUGHT TOLERENCE USING MORPHO- PHYSIOLOGICAL AND YIELD CONTRASTING INDICES

Abstract

Eight genotypes of Onion (Allium cepa L.) were evaluated to find out the genotypes for drought tolerance using morpho-physiological and yield contrasting indices at Sher-eBangla Agricultural University, Dhaka during July, 2021 to June, 2022. The experiment

was

laid out in Complete Randomized Design (CRD) with three replications. Mean performance, genetic parameters, Pearson’s correlation coefficient, and principal component biplot analysis on different yield contributing characters and yield of onion genotypes were estimated. The longest plant (49.43 cm) was recorded in the genotype Lal Teer King, while the shortest plant (20.287 cm) was found in onion genotype BARI Piaj 3. The highest bulb yield/plant (34.50 g) was recorded in the genotype of Lal Teer King, whereas the lowest bulb yield/plant (21.38 g) from the genotype of BARI Piaj 3. Phenotypic coefficient of variation was higher than the genotypic coefficient of variation for all the yield contributing traits indicating drought stress influenced the genotypes. In Pearson’s correlation study, yield per bulb positively and significantly correlated with plant height (0.818), root length (0.511), no. of leaves (0.744), leaf length (0.720), leaf breadth (0.756), bulb length (0.469), bulb diameter (0.716), leaf area (0.893), chlorophyll content (0.886) and dry weight per bulb (0.854). The positive and significant correlation observed between grain yield and traits under-drought stress conditions provided evidence that studied traits might ultimately be considered as a tool for effective selection of drought tolerant genotypes. Path coefficient analysis revealed to that plant height had direct positive effect (5.058), root length had direct positive effect (0.263), no. of leaves had direct positive effect (1.129) and dry weight per bulb had direct positive effect (0.44) on yield per bulb, indicating these were the main contributors to yield per bulb. The study selected 8 genotypes with high grain yields under drought stressed conditions and favorable adaptive traits useful for breeding. In consideration of yield contributing characters and yield Lal Teer King performed better under drought condition followed by BARI Piaj 1, BARI Piaj 2, BARI Piaj 3, Taherpuri, Faridpuri, Bombay and Annex N-53.