Call Prefix : PR-T

Call Suffix : 2017

Call Cutter : D - Agro 35

Location : SEARCA Library

Format : TD

Publisher : University of the Philippines Los Baños

Publication Date : June 2017

Publication Place : Los Baños, Laguna, Philippines

Summary : Agronomists and plant breeders usually rely on the evaluation of various plant traits in the field to select cultivar for further breeding step. Agronomic, physiological traits and yield component traits, and their relationship with grain yield were determined in various germplasm sets in IRRI irrigated breeding program. Physiological and yield component traits were investigated in the Diversity Panel with 36 genotypes in 2015 WS and 2016 DS, 36 genotypes including parent and offspring lines developed by Rapid Generation Advance method (RGA) in 2016 DS, advanced breeding lines of Multi- Environmental Yield Trial (MET) stage at 2015 WS, and advanced breeding lines of Regional- Yield Trial (RYT) and Preliminary-Yield Trial (PYT) under alternate wetting and drying (AWD) and normal irrigation conditions at 2013 DS and 2014 DS. Spectral reflectance measurements for normalized difference vegetation index (NDVI) at key growth stages were done to estimate physiological status of plant genotypes, and evaluate the usefulness of this tool in phenotyping. The NDVI at different growth stage, SPAD at 4 WAH, agronomic traits, yield component traits and yield were collected to measure the heritability, relationship of traits with yield in various germplasm sets. There was a differential response of different germplasms in terms of yield component traits. In Diversity Panel, plant height, the number of panicle per m2, number of spikelets per panicle, HI, 1000 GW, NDVI at heading stage, NDVI at late-grain filling stage and SPAD at 4WAH were highly associated with yield, and thus these traits can be used as reliable selection index for yield improvement during wet season (WS). During dry season (DS), plant height, NDVI at panicle initiation and NDVI at late-grain filling stage were more highly associated with yield. For Diversity Panel, the degree of genetic variation among the genotypes and the different seasons were observed. Plant height, panicle length, NDVI at panicle initiation and NDVI at late-grain filling were highly associated with yield in parent and advanced breeding lines of RGA method during DS. Thus, the improvement of these traits is possible through hybridization followed by selection to release high-yielding variety for DS. The different trait selection for early- and late-maturing lines in MET trail stage could be more effective to identify high-yielding advanced breeding lines. A very strongly association of yield with biomass under water-saving (AWD) condition, and number of spikelets per panicle and HI are good selection traits under both AWD and normal irrigation condition.