Phenotyping for resistance to pre-harvest sprouting in grain sorghum

RODRIGUEZ MARIA VERONICA; ARATA GONZALO JOAQUÍN; DÍAZ, SANDRA MABEL; SANTIAGO RENTERÍA ; BENECH-ARNOLD R.L.

SEED SCIENCE RESEARCH

CAMBRIDGE UNIV PRESS

Lugar: Cambridge; Año: 2021 p. 1 - 10

0960-2585

Pre-harvest sprouting (PHS) is a common threat to cereal crops in which the grain maturationphase takes place under rainy, moist conditions. Susceptibility to PHS is higher in sorghumgenotypes displaying low levels of seed dormancy before harvest maturity. Other attributessuch as glume or panicle morphology may also affect susceptibility to PHS. Breeding forresistance to PHS in grain sorghum requires the identification of grain physiological and morphological attributes affecting this trait, and a protocol for phenotyping and rating genotypesaccording to their susceptibility to PHS. In this work, we tested germination under laboratoryconditions using detached grains and intact panicles for a panel of 20 sorghum genotypesincluding 11 parental lines, 6 hybrids and 3 reference inbred lines with contrasting PHSresponse. Records for natural sprouting in the field for these genotypes were also includedin the analysis. Multivariate analyses of germination data allowed separation of genotypesinto two major categories (resistant and susceptible to PHS). Laboratory germination data correlated significantly with PHS in the field. In most genotypes, the glumes had a significant,inhibitory effect on germination. The low levels of grain dormancy were observed amonghigh tannin backgrounds, and vice versa, indicating that a pigmented testa alone does not provide resistance to PHS. Altogether, the phenotyping protocol allowed the classification of sorghum genotypes according to their susceptibility to PHS and the identification of differentattributes useful for breeding for PHS resistance in this crop