Genetic variability and character association in maize grown in Jammu Province

Maize is an important cereal crop of Jammu and Kashmir State in India. It is cultivated over an area of 2.85lakh hectares, which is more than the area under any other cereal crop grown in the state, including paddy. Only about 10% of this area (0.29lakh ha) is under improved hybrids and/or composites. The rest of the area is still under local adapted varieties. These locals may not be as productive as the hybrids but they possess some useful traits which have helped them to survive long periods of domestication. They could, therefore, be useful material in the development of any superior hybrids suited to this region.

The present study was undertaken to assess the genetic potential of 25 local varieties of maize (Table 1) from the Jammu province of Jammu and Kashmir State. The design for the experiment was a randomized block design with 4 replications at Srinagar. Each entry was grown in one-row plots 12m long, with row spacing 75cm. Plant-to-plant distance was maintained at 25cm and observations were recorded on 10 random plants in each plot. Only those characters were studied which were significant (Table 2). The genotypic and phenotypic coefficients of variability were estimated according to the formula given by Burton (Proc. 6th Int. Grassland Cong. 1:277, 1952) and heritability in the broad sense according to Hanson et al. (Agron. J. 48:268, 1956).

The analysis of variance revealed highly significant differences among varieties for all the characters, suggesting that there was a high degree of genetic diversity in the material for various characters. A wide range of variation was observed for most of the characters. Plant height, leaf index and number of tassel branches per plant showed wide variation, while the number of ears per plant and number of leaves per plant showed a narrow range of variation. In general the phenotypic coefficient of variation was higher than the genotypic coefficient of variation, indicating larger influence of environment on the expression of the characters. However, the number of leaves per plant, plant height and days to 75% silking showed very little difference in genotypic and phenotypic coefficient of variability, indicating that these characters were less influenced by the environment.

Plant height, number of tassel branches per plant and number of leaves per plant showed high heritability (88.46, 83.16 and 81.42% respectively), indicating the importance of these characters in varietal improvement through selection.

Data on the correlation coefficient (Table 3) indicated that the number of leaves per plant had a significant positive correlation with the days to 75% silking at both the genotypic and phenotypic level (r = 0.7468 and 0.5010), indicating a lot of scope for improvement in this character.

Table 1. 25 local varieties from Jammu Province.

Table 2. F values, mean, range, phenotypic and genotypic coefficient of variability and heritability for seven characters in maize.

Table 3. Phenotypic (P) and Genotypic (G) correlation coefficients of various characters with days to 75% silking in maize.

P.N. Jotshi, B.K. Bhat and M.K. Bhan

Please Note: Notes submitted to the Maize Genetics Cooperation Newsletter may be cited only with consent of the authors.

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