Genetic diversity study in search for sources of resistance to the maize weevil among landrace accessions and inbred lines
Material type:
TextPublication details: African Crop Science Society : 2011Description: p. 90Subject(s): Summary: Maize occupies an important position in the world economy and trade as food, feed and industrial crop. Productivity is low in the developing countries due to biotic and abiotic constraints. The maize weevil (Sitophilus zeamais Motsch.) aggravates shortage of food by causing annual postharvest losses of maize of 20% on average. Studies have confirmed quantitative inheritance for storage pest resistance but breeding for traits to improved grain storage have been largely ignored. Genetic variability is important for progress in breeding program and new sources of resistance are needed for effective breeding for resistance to postharvest pests. The objective was to determine genetic diversity among maize genotypes for resistance to maize weevil based on biophysical traits of resistance. One hundred and ninety five genotypes (120 inbred lines and 75 Landrace accessions, including Resistant and susceptible checks) were used as the test crop. The experimental design in the field was an alpha lattice design with two rows of 2 x 5 and three replicates grown in two locations for two seasons. After harvest and drying the cobs were shelled and grain samples of 100g were taken and disinfested by fumigation with phostoxin for 7 days to eliminate infestation from the field. The kernels were placed in 250 ml jars, infested with 50 unsexed insects (maize weevil) and incubated for 3 months. The experimental design in the lab was randomized complete design. The contents in each jar were sieved to separate grains, insects and flour after 3 months. The grain weight loss (%), number of adult progeny, and flour production (%) were measured/ counted. Data on flour produced (%) and weight loss (%) was arcsine transformed while progeny data was log transformed before statistical analyses. The data was subjected to analysis of variance using the GLM procedure of SAS and means separated by least significant difference. There were highly significant (P <0.05) differences among the inbredlines and landrace accessions for maize weevil progeny emergence, grain weight loss and the flour weight. The mean weight loss for the most resistant genotypes in the landraces was 24% and 12.1% in the inbred lines. The most susceptible landraces had an average weight loss of 50.4 and 37 % in the inbred lines. Genetic diversity for maize weevil exists among tropical maize germplasm thus offering opportunity to exploit the variability towards reducing post-harvest storage losses through genetic improvement
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Abstract only
Maize occupies an important position in the world economy and trade as food, feed and industrial crop. Productivity is low in the developing countries due to biotic and abiotic constraints. The maize weevil (Sitophilus zeamais Motsch.) aggravates shortage of food by causing annual postharvest losses of maize of 20% on average. Studies have confirmed quantitative inheritance for storage pest resistance but breeding for traits to improved grain storage have been largely ignored. Genetic variability is important for progress in breeding program and new sources of resistance are needed for effective breeding for resistance to postharvest pests. The objective was to determine genetic diversity among maize genotypes for resistance to maize weevil based on biophysical traits of resistance. One hundred and ninety five genotypes (120 inbred lines and 75 Landrace accessions, including Resistant and susceptible checks) were used as the test crop. The experimental design in the field was an alpha lattice design with two rows of 2 x 5 and three replicates grown in two locations for two seasons. After harvest and drying the cobs were shelled and grain samples of 100g were taken and disinfested by fumigation with phostoxin for 7 days to eliminate infestation from the field. The kernels were placed in 250 ml jars, infested with 50 unsexed insects (maize weevil) and incubated for 3 months. The experimental design in the lab was randomized complete design. The contents in each jar were sieved to separate grains, insects and flour after 3 months. The grain weight loss (%), number of adult progeny, and flour production (%) were measured/ counted. Data on flour produced (%) and weight loss (%) was arcsine transformed while progeny data was log transformed before statistical analyses. The data was subjected to analysis of variance using the GLM procedure of SAS and means separated by least significant difference. There were highly significant (P <0.05) differences among the inbredlines and landrace accessions for maize weevil progeny emergence, grain weight loss and the flour weight. The mean weight loss for the most resistant genotypes in the landraces was 24% and 12.1% in the inbred lines. The most susceptible landraces had an average weight loss of 50.4 and 37 % in the inbred lines. Genetic diversity for maize weevil exists among tropical maize germplasm thus offering opportunity to exploit the variability towards reducing post-harvest storage losses through genetic improvement
Global Maize Program
English
Lucia Segura
INT2940|INT2460|INT2869
CIMMYT Staff Publications Collection
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