Authors: Kai Wang Fulin Qiu Wenceslao Larazo Madonna Angelita dela Paz Fangming Xie
Publish Date: 2014/12/16
Volume: 128, Issue: 3, Pages: 421-430
Abstract
Heterotic groups are of fundamental importance in hybrid crop breeding This study investigated hybrid yield yield heterosis and combining ability within and among groups based on genetic distance derived from singlenucleotide polymorphism markers The main objectives of the study were to 1 evaluate the magnitude of yield heterosis among markerbased groups 2 identify possible heterotic groups for tropical indica hybrid rice and 3 validate heterotic patterns concluded from a previous study Seventeen rice parents selected from improved indica germplasm from the tropics with high genetic divergence and 136 derived hybrids were evaluated in five environments The hybrids had more yield than their parents with an average of 241 midparent heterosis Genotype × environment interaction was the major factor affecting variations in yield and yield heterosis which raised a necessity and a challenge to develop heterotic rice hybrid adapted to different regions and seasons in the tropics Yield yield heterosis and combining ability were significantly increased in intergroup than in intragroup hybrids Four heterotic groups and three promising hybridization patterns which could be used in tropical hybrid rice breeding were identified based on markerbased grouping yield and yield heterosis analyses in the two studies The study reveals that molecular markers analysis can serve as a basis for assigning germplasm into heterotic groups and to provide guidelines for parental selection in hybrid rice breedingThe authors thank Philippine Rice Research Institute’s Thelma F Padolina and Rustum C Braceros in Muñoz Nueva Ecija and Democrito B Rebong II in San Mateo Isabela for providing field facilities and field management of the field trials in the two locations This research was partially supported by the China Scholarship Council Grant No 2011325040
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