Some Genetic Parameters of Double Crosses under Different Planting Dates Suitable to the Middle Region of Iraq

Abstract

With the aim of estimating some genetic parameters of double crosses at sowing dates appropriate to the fall season in the middle region of Iraq, a field experiment was conducted in the fields of the College of Agricultural Engineering Sciences - University of Baghdad - Al-Jadriya for the fall season 2022 using superior double crosses of maize were chosen from fifteen double crosses. It was obtained from the crossing of ten single crosses resulting from the crossing of five inbred lines (1=ZM43WIZE, 2=ZM60, 3= ZM49W3E, 4=ZM19, 5=CDCN5) by the half-dialle crossing method. Hybrids (3×5)(1×4),(3×5)(1×2),(2×4)(1×5), (4×5)(1×2), and (2×3)(1×4), compared it with the synthetic cultivar IPPA 5012 and tested it under three planting dates:1st July, 15th July and 1st August. The Randomized Complete Block Design (RCBD) was used with four replicates. The traits were studied: tassling, silking, plant height, ear height, number of leaves, leaf area, ear length, ear diameter, number of rows, number of grains per row, number of grains in a row, number of ears, average grain weight, dry matter weight, physiological maturity, ear weight, plant growth rate, individual plant yield, unit area yield, and. harvest Index. The results of the genetic analysis showed that the value of the standard error was low in all traits except for leaf area, number of plant seeds, and in the three dates, and the values of the coefficient of variation (C.V) on1st July were less than 20 in all traits except for individual plant yield, area unit yield, harvest index, and time. 15 th July and 1st August were also less than 20, and the values of genetic variance at the date of 1st July were greater than the values of environmental variance in most of the studied traits, except for ear height, ear length, ear diameter, number of rows, and ear weight. The ratio of genetic variation to environmental variation, as it was less than 1, and it had P.C.V values higher than G.C.V.The number of grains in the row, the weight of the dry matter, the physiological maturity and the plant growth rate due to the high genetic variance for it and the values of the ratio of genetic to environmental variance and then the high heritability values for it and on the date 1st August and the values of the genetic variance were greater than the values of the environmental variance in most of the studied traits.