Comparison of selection indices differetn weights in maize (Zea mays L.) for different biometrical characters

Abstract

The data on six different biometrical characters of fifty seven genotypes/hybrids of maize were collected from Main Maize Research Station (MMRS), A.A.U., Godhara during Rabi season of the year 2015-16 for the present study entitled "Comparison of selection indices using different weights in maize (Zea mays L.) for different biometrical characters". The experiment was conducted in randomized block design with three replications. Six characters grain yield per plant, cob height, cob length, number of grains per row, number of rows per cob and 100 kernel weight were used. The selection index technique was employed to study the crop improvement using different characters giving different weights to each character. Selection index for all possible combination of six characters can be calculated and the combination which provides the higher relative efficiency is selected. Selection index for all possible combination of six characters which provides the high percent relative efficiency (PRE) is selected. For this present investigation, three different weights i.e. equal weight, genotypic correlation and phenotypic correlation were given to different characters to construct selection indices to select the optimum index in maize. Total 63 selection indices were constructed for each weight method. In general higher percent relative efficiency (PRE) was observed for equal weight method among all three weight methods. The selection index (I₁₂₃₄₆) having grain yield per plant, cob height, cob length, number of grains per row and 100 kernel weight had the highest per cent relative efficiency (PRE) among all the combinations of selection indices in equal weight, genotypic correlation coefficient and phenotypic correlation coefficient weight methods. The rank correlation among different methods for selection index values were found positive and highly significant indicating agreement with all methods except equal weight. Therefore index based on equal weight taken is considered better than all other indices. The selection index without grain yield I₂₃₄₆ =0.492 X₂+2.275X₃+0.649X₄+1.125X₆ is the best indices. Where, X₂= cob height (cm), X₃ = cob length (cm), X₄ = number of grains per row and X₆ = 100 kernel weight (g)