RECURRENT SELECTION FOR YIELD AND YIELD ASSOCIATED TRAITS UNDER LEAF BLIGHT (Helminthosporium maydis) STRESS IN MAIZE

Evaluation of S1 lines per se is a popular method of recurrent selection for improving quantitatively inherited traits in maize. To evaluate the efficacy of S1 line recurrent selection for yield and yield related traits in maize under maydis leaf blight (MLB) stress, one cycle of S1 line recurrent selection was conducted in maize variety Sarhad White (SW) at the Plant Breeding and Genetics Research Farm, NWFP Agricultural University, Peshawar during 2007. In spring (March-June), the base population from the third cycle of S1 line recurrent selection was sown in the field and manual self pollination was carried out for S1 line production. During the following season (July-October), the S1 lines were evaluated for resistance to MLB under artificial inoculation for yield and yield components. Highly significant differences (P 0.01) among the S1 lines were observed for ear length, kernel rows ear-1, 1000 kernel weight, grain yield, MLB severity and area under disease progress curve (AUDPC). Selection differential was positive for ear length, kernel rows ear-1, 1000 kernel weight and grain yield whereas it was negative for MLB severity and AUDPC, indicating a declining trend for these two disease parameters. All the yield and yield related traits were negatively correlated with MLB severity. On the basis of frequency distribution curve, most of the S1 lines were in the range of 0.5-1.75, displaying moderate resistance to MLB. The present study revealed the effectiveness of S1 line recurrent selection for enhanced resistance to MLB and improvement of yield and yield associated traits.