Responses to Chilo Partellus Borer Damage in CIMMYT Tropical Maize Landraces.

Abstract

Maize ear characteristics are important in determining grain yield and factors affecting ear development influence yield. Lepidopteran stem borers are major pests of maize the sub-Saharan Africa region and in Kenya, contribute about 13% of yield loss. The objective of this study was to determine the relationship between Chilo partellus damage parameters and maize ear characteristics. The germplasm evaluated were 69 local landrace accessions sourced from International Maize and Wheat Improvement Center (CIMMYT), and 6 hybrid checks. The design was alpha lattice replicated three times at Kiboko-CIMMYT field station in Kenya for two seasons. Plants were artificially infested with five borer neonates three weeks after planting. Parameters measured were leaf damage score, stem exit holes, stem tunnel length, ear and cob diameter, ear length and grain yield. Data was analyzed using SAS package and means separated using LSD procedure at P<0.05 level. An insect damage index was developed and used to classify germplasm into resistant and susceptible. Susceptibility increased with increase in number of stem exit holes and tunnel lengths. GUAT 1050 was the most resistant landrace while Braz 2179 was the most susceptible. Though not significant, ear characteristics were negatively correlated to all damage parameters evaluated, but positively and highly correlated to grain yield and other grain yield components.