A study of New Zealand wheats

Abstract

At different stages of development single-tillered plants of Hilgendorf 61 wheat growing in a glasshouse were subjected for 3 hr to - 1°, - 2°, + 38°, or +40.5 c in the dark, preceded by a 2-day conditioning period. Applied at the double-ridge stage, none of the treatments had any effect, hut grain yield was greatly depressed by extreme temperature during anthesis and early grain development. Grain number was decreased by exposure to -2° but not -1°c. High temperature during anthesis reduced grain number and single-grain weight, but later treatment affected only single-grain weight. Reduction in grain number was attributed to floret sterility.