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|Authors:||Patil, Jagannath Daji|
|Title:||GENETIC VARIABILITY AND CORRELATION STUDIES IN ONION (Allium cepa L.)|
|Publisher:||MAHATMA PHULE AGRICULTURAL UAIVERSITY RAHURI. (Dist: Ahmednagar) ( Maharashtra State, India )|
|Abstract:||Forty-five onion cultivars collected from different geographic regions of India were studied for their variability in morphological, biochemical and storage characters of onion bulbs. The significant differences were observed among. the onion cultivars in reapect of morphological, biochemical and a high magnitude of variability in the cultivara study. The estimates of genotypic coefficient of variation were low as compared to the phenotypic coefficients of variation. Very high heritability were obtained for the characters per cent sprouting (98.97 %; followed by per cent rotting; '97.74. Most of the storage characteristics, biochemical characters except non-reducing sugar andi morphological characters showed very high estimation of heritability but comparatively lower genetic advance, while moderate to high heritability values with high genetic advance ware observed for the characters total loss, bulb weight, percent sprouting and percent bolting. Thus, additive genetic effects were observed for these characters which can be improved by selection, The bulb weight showed positive correlation with bulb diameter (both polar and equatorial;, neck thickness, diameter of root plate, number of leaves per plant, dry natter content and percentage of sprouting while it was negatively correlated with per cent boltinq, Tss content and non-reduction sugar at genotypic and phenotypic level. The total loss was positively correlated with height of plant, neck thickness, bulb diameter (polar), number of leaves per plant, belting, non-reducing; sugar and total sugars while it was negatively correlated with T33 and dry matter content at phenotypic as well as genotypic levels During the six month storage period April to sept.1983, the TSS, dry matter content and non-reducing sugars were found to increase. The rotting PLW losses occurred throughout the storage period which were favoured by prevailing high temper. tures, while the losses due to sprouting were observed only during the period from July to September where the temperature was comparatively low and the atmospheric humidity was high. Out of 45 onion cultivars, only two cultivars viz. Large Red and HNS-2 recorded the minimum total loss of 64.86 per cent and 64.19 per cent respectively. None of the cultivers showed total storage losses below 70 per cent., 2 he D2 statistics showed that there was adequate diver- sity among the cultivars with D2 values ranging from 36.87.to 3557.35. On the basis of these values forty-five cultivars under study were grouped under 12 clusters and a tentative breeding programme has been suggested. Clustering pattern of these cultivars does not necessarily follow the geographical distribution.|
|Appears in Collections:||Thesis|
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