Identification of Gray Leaf Spot Resistance among Selected F\(_2\) Maize (Zea mays L.) Population Using Simple Sequence Repeat Markers

Abstract

Maize is a highly nutritious cereal grain that plays a crucial role in global food security. Maize (Zea mays L.)  productivity in Kenya is low, 1.5-2.0 t ha-1, against the potential of 5 t ha-1. Low yield is partly due to gray leaf spot (GLS) disease and lack of locally bred and adapted cultivars.  There is need to accelerating maize breeding programs by incorporating molecular breeding, in  selecting genotypes with desired traits. The objective of this study was to determine the resistance to gray leaf spots in selected F2 maize population through the use of simple sequence repeat (SSR) markers. A total of 23 maize genotypes were evaluated, including 13 F2 population, eight Parental inbred genotypes, and two commercial checks. The amplified DNA fragments were visualized on a 2% agarose gel, and the bands were scored for the presence (+) or absence (-) of the targeted GLS resistance gene. DNA from 23 genotypes analysed, revealed a resistance-associated region at 164 bp. Different banding patterns indicated variations in the GLS resistance gene among genotypes. Marker CPrI-117757 produced a distinct band most genotypes.  Markers l 1258, Bnlg 1194, and Phi 031 amplify bands in the genotypes. Different banding patterns indicated variations in the GLS resistance gene among genotypes. The total of effective alleles was 5.554 and the number of alleles per primer ranged from 0.00 to 1.00. The effective number of alleles was lower than the observed number. Furthermore, GLS genetic variation among the genotypes the was significant suggesting that most genetic diversity for GLS resistance is structured among groups rather than within the genotypes. Markers CPrI-117757 may be associated with traits relevant to gray leaf spot resistance and could be used in to tag resistance genes for GLS in maize