Adaptability of onion (Allium cepa) genotypes to alkali and salinity stresses

Adaptability of onion (Allium cepa) genotypes to alkali and salinity stresses

2000

A:PS

The performance of seven onion (Allium cepa) genotypes ('Pusa White Flat', 'Agri Dark Red', 'PBR 5', 'Amrawati', 'Pusa White Round', 'Phule Safed' and 'Agri Light Red') was evaluated during rabi 1995 and 1996, both under alkaline (pH 9.20, 9.45 and 9.70) and salinity (ECe 3.5 and 5.2 dS/m) stresses besides a non-stress control. Under increasing alkaline stress, mean seedling fresh weight declined, ranging from 32% (pH 9.2), through 54% (pH 9.45) to 85% (pH 9.7), compared to the control. In general, onion bulb yield declined by 41 and 49% at pH 9.2 and 9.45, respectively, compared with the control, and dropped to negligible level at pH 9.7. On average, over different alkaline levels, 'Amrawati' gave maximum bulb yield followed by 'Agri Light red'. 'Agri Light Red' recorded minimum reduction both in seedling fresh weight and final bulb yield up to pH 9.45. Further, under salinity stress, seedling fresh weight declined by 13 and 26% while mean bulb yield (at harvest) declined by 54 and 65% at ECe 3.5 and 5.2 dS/m, respectively. Highest mean bulb yield obtained under salinity was by 'Pusa White Flat' followed by 'Amrawati' amongst the different genotypes tested. Simultaneously, minimum reduction of 38 and 46% in bulb yield was observed in 'Pusa White Flat' at ECe 3.5 and 5.2 dS/m. Final bulb yield was positively correlated with seedling fresh weight both under alkaline (r = +0.86) and salinity (r = +0.56) stresses. Similarly, bulb yield was negatively correlated with Na/K ratio under alkaline (r = -0.83) and salinity (r = -0.79) stresses. A 50% reduction in bulb yield was observed at pH 9.14 and ECe 3.93 dS/m.

v.70(10):674-678, INDIAN JOURNAL OF AGRICULTURAL SCIENCES

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