Abstract:
This study was aimed to assess the effects of excess boron on 59 genetically divergent
wheat accessions and to identify those with high and stable yields under a range of soil
boron concentrations. The second aim was to test the applicability of a laboratory
technique performed at juvenile stages of development in estimating field boron
tolerance. The study comprised a control and three boron treatments, applied as 50, 100
and 150 mg boric acid L-1 in laboratory, and 33.0, 67.0 and 133.0 kg boric acid ha-1 in field
trial. Yield performance and stability were evaluated using biplots from sites regression
model, while interrelationships among analyzed parameters were assessed using path
coefficient analysis. Parameters were mostly decreased by excess boron when compared
to the control (seedling root length, seedling dry weight, grain number per spike, grain
yield, flag leaf area, leaf area duration and grain weight). Significant increase was noted
for seedling boron concentration and content, percentage of sterile spikelets per spike and
number of spikes per m2. Spike length, number of spikelets per spike, and anthesis date
remained unaffected. The majority of accessions with high and stable yields were of local
origin, so, we conclude that adaptation to environmental factors other than elevated soil
boron plays an important role in overall field boron tolerance. The effects of excessive
external boron on boron accumulation noted at the seedling stage in laboratory studies
corresponded to its effects on yield in field.
Keywords: Micro-element boron, Path coefficient, Sites regression model, Triticum
aestivum, Yield stability.
