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|Authors:||Shaha, Suresh Ratanchand|
|Title:||GENETIC DIVERGENCE AND VARIABILITY STUDIES IN ONION (Allium cepa L ) By|
|Publisher:||MAHATMA PHULE AGRICULTURAL UNIVERSITY RAHURI, (Dist: Ahmednagar) (MAHARASHTRA)|
|Abstract:||Forty-two onion cultivars obtained from different geographic regions were evaluated for their morphological and biochemical variability and genetic diversity in bulb characters and storage quality. Significant differences were observed among the onion cultivars for these characteristics indicating high magnitude of variability in the genotypes under study. The estimates of PCV were higher as compared to GCV. Very high heritability was obtained for the character per cent sprouting followed by per cent total loss. High heritability value with high genetic advance was observed for the characters bulb weight, per cent total loss, per cent sprouting and per cent bolting indicating high additive genetic variance, and hence, these characters can be improved by selection. The bulb weight was significantly and positively correlated with bulb diameter (both equatorial and polar) neck thickness, while it was negatively correlated with per cent bolting, dry matter, TSS content (after storage) and non-reducing sugar. The per cent total loss was significantly and positively correlated with equatorial bulb diameter, neck thickness, per cent rotting, sprouting and PLW losses, while it was negatively correlated with polar bulb diameter, dry matter, TSS and sugar content. The mean total losses recorded during the 5 months storage period (1st May 1984 to 30th September 1984) due to rotting, sprouting, PLW and total losses were 5.88%, 33.22%, 32.43% and 71.53 %, respectively. Out of 42 cultivars, 34 and 8 had red and white bulb colour, respectively. Seven cultivars N-257-9-1, Udaipur-101, Kondapuri-1, Adsuli, N-2-4-1, Udaipur-102, and Pusa Red recorded less than 50% total storage losses. Cultivar N-257-9-1(31.63%) followed by Udaipur-101 (33.93 %)recorded the least storage losses and were found promising,, During the 5 months storage period, TSS and dry matter content was found to increase. In white cultivars, significantly lower losses due to sprouting, PLW and total loss were observed than red culti vars. There were no significant differences in per cent dry matter, TSS content before and after the storage and rotting in the white and red onion cultivars«, The D statistics revealed that there was wide diversity among the strains with D2 values ranging from 46.23 to 6773.56. On the basis of D2 values, 42 onion cultivars were grouped under 14 clusters which do not necessarily follow the geographical distribution. A tentative breeding programme has been suggested.|
|Appears in Collections:||Thesis|
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