Studies on some hybrids and strains of yellow maize

Abstract

The aim of the present investigation was to detennine the estimates of combining ability and heterosis for fifteen quantitative characters of yellow maize, viz. (Tasseling and silking date, plant and ear height, stem diameter, number of ears per plant, ear length, ear diameter, number of rows per ear, number of kemels per row, 100-kernel weight, shilling percentage, grain yield per plant and grain yield ardab/feddan) wtder two plant densities, (j.e. 20 000 (D1) and 30 000 (D2) plants/feddan for crosses and 30 000 and 40 000 plants/fad for parents) in 55 genotypes (ten parental lines and their 45 crosses. Also, to detennine the interaction of genetic variance components and heterosis with plant density besides defining the most superior single crosses to utilize it in improving maize breeding programs. The experimental work of this study was conducted during two successive growing seasons started in 1999 at the Experimental Farm of the Faculty of Agticulture, Ain Sham University, Shoubra El Keima in the first season. and lasted at the Experimental Farm of the Faculty of Agriculture, Ain Sham University, Shoubra El Keima, Kalubia Govemorate in the second season 2000. Ten maize inbred lines namely. PI (24 Turkish inbred line), P2 (BS-10-8), P3 (I-l-111), P4 (BS-10-3), P5 (Roh.43Ht, B), P6 (BS-10-l), P7 (R38- 11Ht, B), P8 (CM 103), P9 (CM 104) and P\0 (CM 202), were used for this study. Inbred lines were crossed in a diallel mating system (excluding reciprocals) during 1999 season to obtain a total of 45 hybrids in 2000 growing season, the 45 Ft 's along with their parental inbred lines were grown under two different plant densities at one experiment. Whereas it designated in a spilt plot experimental arrangement of randomized complete blocks design with tluee replicates in which two plant densities were allocated to