STUDIES ON VARIABILITY AND STABILITY UNDER DIFFERENT POPULATION DENSITY LEVELS IN GRAIN AMARANTHUS (Amaranthus hypochondriacus L.)

Rameshkumar - Selvan
Horticulture, Tamilnadu Agricultural University
July, 2008
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Abstract

In grain amaranthus (Amaranthus hypochondriacus L.) ten genotypes were evaluated for thirteen characters under four plant density levels viz., very high (D1), high (D2), normal (D3) and low plant density (D4) levels to study the variability parameters, character association and stability. The study was conducted at Pandit Jawaharlal Nehru College of Agriculture and Research Institute, Karaikal during rabi 2007. Grain yield per plant was reduced in very high and low plant density levels mainly because of reduction in length of the primary inflorescence, fresh weight of the inflorescence, number of secondary branches per inflorescence and leaf area at 50 per cent flowering when compared to high and normal plant densities. The high plant density produced the highest grain yield per plot which was mainly due to the number of plants per unit area was higher under this density level than normal and low plant density levels which could increase the grain yield per plot. Based on the mean performance, Annapurna was identified as ideal genotype performing superior under all the four plant density levels followed by the genotype EC 519554 for most of the yield and yield attributing characters. Plant densities altered the estimates of genetic variability, heritability and genetic advance as per cent of mean. The characters viz., leaf area at 50 per cent flowering, fresh weight of the inflorescence, number of secondary branches per inflorescence and total carbohydrates registered high genetic variability in combination with high heritability and genetic advance in all the plant density levels, revealing the possibility of improvement of these traits through a simple selection programme. Correlation and direct effect of component traits on grain yield were, in general, highly influenced by the plant densities both in direction and magnitude. The fresh weight of the inflorescence, length of the primary inflorescence and number of secondary branches per inflorescence recorded strong positive correlation with grain yield as well as strong inter correlations among themselves, indicating that improvement of grain yield in amaranthus could be achieved by exercising selection for these component traits. The path analysis revealed that fresh weight of the inflorescence, leaf area at 50 per cent flowering, length of the primary inflorescence and number of secondary branches per inflorescence had direct positive effects on grain yield. Based on the stability analysis, the genotype Annapurna was identified as stable genotype for grain yield in all the four plant density levels. The genotypes BGA 2, GA 2 and IC 415290 recorded stable performance for total carbohydrates and protein content and could be utilized for improvement of these traits in breeding programme. The genotype GA 2 showed stable performance for fresh weight of the inflorescence, an important trait influencing the grain yield in all the four plant density levels. Similarly, SKNA 601 can be chosen as stable genotype for leaf area at 50 per cent flowering, an important selection parameter for yield improvement in all the plant density levels. Among the characters studied, length of the rachis per inflorescence, total carbohydrates and protein content were found to be relatively stable in all the four plant density levels.