S1-PROGENY SELECTION FOR DROUGHT' N' K STRESSES IN MAIZE 1-Some field traits

Abstract

In order to develop selected communities with high yield and water stress tolerance, the effect of selection on maize (Zea mays L.) yield and growth improvement was studied under some abiotic stresses (water, nitrogen, and potassium) with four fertilizer combinations (K100 N250, K200 N250, K100 N500, and K500 N200). A field experiment was conducted during six seasons(2009-2011) in the field of Crop Science Dept. – College of Agriculture – University of Baghdad. In this experiment, the synthetic cultivar, Ibaa 5012 was used. The selection depended on grain yield under sufficient and insufficient water. The plants were selected from each group of combination according to phenotypic superiority, and undergone to self pollination for three cycles under sufficient and non sufficient water. In the fourth season, the manual random mating was used between selected plants in each group, the resulted seeds from random mating were divided into two groups, which were planted in a comparative experiments for spring and autumn seasons under irrigation levels(5 and 10 days), to compare them with the origins under tow plant densities (60 and 80 thousand plant/ha). Results showed the superiority of plants selected from 10 days irrigation. Plant high increased 4.6 and 7.6 cm for SDN2K2 in spring and fall season respectively. Leaf number increased for all selective over origin population. Leaf area and LAI increased 18% ,16%in Spring season and 15%,19% in fall season forSDN2K2 respectively. Selection cycles also affected the field characters of all selected plants under sufficient water (5 days) in the same way. Plant high decreased 20 and 15cm for SN2K2 in both seasons. Leaf number increased for all selected plant .Leaf area increased 11% ,10%,4% and12%,3%,6% in spring and fall seasons respectively. LAI increased 11%,9%,4% and 13%,5%,7% forSN1K1,SN1K2,SN2K1 in spring and fall seasons respectively too So we recommend the selection for high yield and device lines that tolerant to both of dry stress and high plant density to be used in breeding programs under abiotic stresses and producing improved cultivars suitable to our environments or to be crossed to produce distinguished hybrids.