A comparison of the growth and development of biculm wheat lines with freely tillering cultivars

Publisher Website
Google Scholar
Abstract
The growth, development and grain yield of two low-tillering lines of wheat of Israeli origin were compared with those of two freely tillering Australian wheat cultivars (Gamenya and Egret) in field plots. The majority of individuals from the low-tillering selections were uniculms or biculms. Detailed observations were made on the main shoot of the biculms. There was no difference in the duration of primordia production by the main shoot apex between genotypes but the rate of initiation of spikelet primordia in the lowtillering lines was significantly greater than that of the tillering cultivars and this resulted in a large ear with more spikelets. The rate of leaf appearance was very similar in all genotypes but the later-appearing leaves of the biculms were very large in comparison with those of the cultivars. The majority of the biculms produced the tiller in T3 position. At maturity the main shoot and tiller of biculm individuals produced 60 and 40% respectively more dry weight than the equivalent shoots of the tillering cultivars. The total biomass per plant of the biculms was similar to that of Egret but less than that of Gamenya. The grain yield of the main shoot of the biculms was 50% greater than that for the tillering varieties and this was associated with an increase in the number of grains per ear as there was little difference in grain size. In the biculm a high proportion of the spikelets in the mid part of the main shoot ear produced five grains; grains from basal florets were significantly larger than those of upper florets mainly because they had a longer duration of growth. Overall the grain yield of the two tillering cultivars, either per plant or per metre of row length, was approximately 30% greater than that of the low-tillering selections. The greater growth of the main shoot axis in the biculms therefore did not compensate for the grain contributed by the tillers of the freely tillering cultivars.