Response of maize population “Longe5” to two cycles of modified S1 recurrent selection for resistance to maize weevil

Abstract

The maize weevil (Sitophilus zeamais Mostch.) is one of the most damaging storage pests causing significant reductions in grain weight and quality in tropical and subtropical regions. The current study determined the effectiveness of two cycles of modified S 1 recurrent selection towards the improvement of weevil resistance in the maize variety ''Longe5''. Grain yield and resistance to Turcicum leaf blight, grey leaf spot and rust diseases, which occurred naturally at the time of experimentation, were also evaluated to enhance the overall worth of the maize variety. Selections were made by identifying and self-pollinating the foliar disease resistant and vigorous plants, with potentially big well-placed ears from the base population of the Longe5 (the original cycle i.e., C 0 ), grown at the National Crops Resources Research Institute, Namulonge, in Uganda. Over 540 selfed ears were obtained from the C 0 and were screened for maize weevil resistance under controlled conditions in the laboratory, after which 162 weevil resistant genotypes were selected and recombined in an isolated field to generate the C 1 . The second cycle (C 2 ) was generated from the C 1 in a similar procedure, by recombining 190 weevil resistant genotypes. The C 0 , C 1 , and C 2 were evaluated for grain yield and reaction to foliar diseases at three locations, and the ensuing seed was screened for maize weevil resistance in the laboratory. Significant gains were obtained for maize weevil resistance. There was a reduction in grain weight loss due to maize weevil damage of 65 % in C 2 and 15 % in C 1 . There was a 33 % reduction in the number of weevil progenies emerging in C 2 and 19 % in C 1 grain. Similar positive trends were realized for grain yield and resistance to foliar diseases in C 1 and C 2 compared to C 0 . The results indicate that the modified S 1 recurrent selection was effective in improving Longe5 for maize weevil resistance.

Evaluation of early-generation tropical maize testcrosses for grain-yield potential and weevil (Sitophilus zeamais Motschulsky) resistance

“…Maize weevil mortality was not significantly different among the genotypes. This is consistent with results by Dhliwayo et al (2005) and Kasozi et al (2015) but in contrast to findings by Nhamucho et al (2017) who reported significant differences in maize weevil mortality among Mozambican local and improved maize genotypes. Mortality maybe attributed to presence of a fluorescent pericarp with high concentration of hydroxycinnamic acid ( Serratos et al, 1987 ).…”

“…Assessment of grain weight loss among hybrids revealed significant variation suggesting presence of genotypic differences in maize weevil resistance in this germplasm. Similar findings were reported by Tefera et al (2011) , Masasa et al (2013) , Zunjare et al (2014) , Derera et al (2014) and Kasozi et al (2015) in studies with different types of maize germplasm. The large variation for grain weight loss for these germplasm means that the selection could be an effective strategy for maize weevil resistance improvement.…”

“…Resistance to maize weevil as measured by number of damaged kernels showed highly significant variation among the hybrids. Siwale et al, 2010 , Abebe et al (2009) , Masasa et al (2013) and Kasozi et al (2015) also reported significant variation among hybrids. The weight of powder produced after eating by the maize weevil did not differ significantly among the hybrids, which suggested successful infestation and feeding by the insects.…”

Control strategies and breeding efforts in sorghum for resistance to storage weevils

“…Kasozi et al (2015) used two cycles of modified S1 recurrent selection to study resistance to maize weevil in maize. The authors found that the modified S1 recurrent selection was effecttive in improving Longe5 for maize weevil resistance.…”