Divergent selection for sprouting resistance in spring wheat

The development of sprouting-resistant spring-wheat ( Triticum aestivum L.) cultivars is a major breeding objective in many wheat-producing regions. Sprouting resistance is thought to be associated with delayed maturity. The primary objective of this study was to measure the reciprocal effects of selection for sprouting resistance and maturity. Two experiments were conducted over a 3–4-year period in Saskatoon, Canada. In the first experiment, two populations of hard red spring wheat were subjected to divergent selection (k = 10%) for maturity. In the second experiment, six populations derived from crosses between two sprouting-resistant, late-maturing, white-grained cultivars ('AUS1293' and 'AUS1408') and three early maturing, red–grained cultivars ('Park', 'PT516' and 'Roblin'), were subjected to divergent selection (k = 10%) for sprouting resistance. Selection for earliness reduced sprouting resistance in one population but had no effect in the second. For both populations, earlier maturity was associated with higher test weight but lower grain yield. In the second experiment, selection for increased sprouting resistance was effective, with realized heritabilities averaging 0.74. Increased sprouting resistance was associated with a slight delay (1–2.5 days) in time to spike emergence in four out of six populations, but had little effect on time to maturity in most populations. There was a trend towards redder grain in the sprouting-resistant selections. The recovery of sprouting-resistant, early maturing segregants was relatively low, averaging less than 10% over the six populations. In conclusion, selection for increased sprouting resistance can result in delayed maturity, but the magnitude of that delay will vary among populations.