Analysis of diallel crosses of maize (Zea mays L.) populations for resistance to fall armyworm (Spodoptera frugiperda Smith, 1797, Lepidoptera: Noctuidae)

Author(s)

Maria Del Pilar Alvarez

• Document type: Doctoral Thesis
• Press: Piracicaba.
• Institution: Universidade de São Paulo (USP). Escola Superior de Agricultura Luiz de Queiroz (ESALA/BC)
• Defense date: 2001-09-03
• Advisor: Jose Branco de Miranda Filho

Abstract

The main objective of this work was to evaluate new sources of resistance to fall armyworm (Spodoptera frugiperda, Smith, 1797, Lepidoptera: Noctuidae), the key pest for maize culture in Brazil A partial diallel design between 20 varieties of Brazilian germplasm and 9 exotic and semi-exotic varieties of different origins was used. The 180 crosses and 29 parental varieties along with two commercial checks were evaluated in three locations placed in São Paulo State (Brasil). Fall armyworm resistance (FAWR), under artificial and natural infestations, grain yield (GY), and plant height (PH) were measured. Populations CMS14C and MIRT, and hybrid São José x MIRT presented highest resistance, with values of 1,8; 1,7 e 1,4, respectively. Populations PMI9401 and PR91 B, and hybrid CMS14C x B97.Ituiutaba had best yields, with 4893, 3858 and 5677 kg/ha, respectively. Heterosis range from -28% to 47% for FAWR and from -21% to 125% for GY, with mean values of -0,43% and 31%, respectively. Genotype by environment interaction was not significant for FAWR. Additive and non additive effects were found for this characters. They may be advantageous for the implementation of intra and/or inter-population recurrent selection programs. Additive and non additive effects were estimated for GY and mainly additive effects for PH. Brazilian populations PMI9302 and São José, and exotic population PR91B presented high performance per se and in crosses for FAWR and GY. Crosses (PMI9401 x Cuba110.EsalqPB1) and (São José x MIRT) presented high specific heteroses effects for both characters. This populations are useful to be introgressed in maize breeding programs. (AU)