16. Development of S1 inbred lines and estimation of inbreeding depression in two maize (Zea mays L.) populations
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Abstract
To know the effect of inbreeding depression, this study was conducted in the Agricultural Experimentation Block of the University of Swabi, during the two cropping seasons of 2013-2014. The S1 inbred lines were developed from two of the maize populations viz. popcorn (‘PC’) and sweet corn (‘SC’). Plant height (PH), ear height (EH), ear length (EL), leaf area (LA), number of leaves (NL) and number of tassel branches (TB) were investigated. Highly significant differences (P≥0.01) were observed for PH and LA in S1 lines however; this effect was non-significant within the parental population. While the rest of the traits did not show any significant variation in the first generation of inbreeding (S1). Of the developed 20 S1 inbred lines, mean data revealed that maximum reduction in PH (169.55 cm) was in the set of inbred lines obtained from ‘PC’ as compared to that of ‘SC’ (159.65 cm). Similarly, reduction of 44.92 cm2 was noticed in LA of ‘PC-S1-4’ as compared to the lines developed from ‘SC’. The results indicated that except PH and LA, other traits like EH, EL, NL and TB are closely linked and hence in first generation of selfing there was not a significant variation in the S1 developed from ‘PC’ and ‘SC’. However, the potential inbred lines need to be re-evaluated for diversity, GCA and SCA when homozygosity is complete in later generations.
Keywords: Zea mays L.; Inbred line; Popcorn; Sweet corn; Inbreeding depression