Lm. Dwyer et al., MAIZE PHYSIOLOGICAL TRAITS RELATED TO GRAIN-YIELD AND HARVEST MOISTURE IN MID-SEASON TO SHORT-SEASON ENVIRONMENTS, Crop science, 34(4), 1994, pp. 985-992
Identification of easily measured physiological traits contributing to
yield under specified environmental conditions would benefit genotypi
c selection for maize (Zea mays L.). A field experiment was conducted
to determine relationships between grain yield, harvest moisture, the
ratio yield/moisture (Y/M), and 10 maize physiological traits related
to development time, vegetative growth, and partitioning to the grain.
Nine commercial hybrids, representing three maturity classes from 75
to 95 d, were planted at three sites with zonations, based on corn hea
t units (CHU), corresponding to the three maturity classes within 100
km of Ottawa, Canada (45 degrees 22' N, 75 degrees 43' W), in 1988, 19
89, and 1990. Grain yield and harvest moisture were related to hybrid
maturity; i.e., late maturity hybrids produced high yields with high g
rain moisture, but traits related to development time alone did not pr
edict yield and moisture. Traits most highly correlated with grain yie
ld and Y/M for the three maturity classes at the three sites were harv
est index, vegetative dry matter (at tasselling), time to develop betw
een silking and maturity (TFILL), and time to develop to silking (TSIL
K). Traits most highly correlated with harvest moisture were time to d
evelop to maturity, TSILK, and TFILL. Models to estimate grain yield h
ad higher coefficients of determination than those for harvest moistur
e and models for Y/M had intermediate coefficients. Results suggest th
at selection for high yielding low moisture hybrids in mid- to short-s
eason production areas should aim to increase (i) the grainfilling per
iod (TFILL); (ii) vegetative dry matter; and (iii) harvest index.