VARIATIONS OF BREADWHEAT TRAITS AND SELECTION ACTION AS INFLUENCED BY HONYCOMB SPACINGS

Abstract

A field experiment was conducted in 2006 and 2007 to identify the best spacing of the honeycomb selection to show cultivars variation. The experiment included the bread wheat cultivars IPA99 and Abu-Ghraib3 and distances between plants (d) (30-90 cm) with 20 cm increment, and between row according to the equation d√3/2 . The experiment was conducted by using RCBD with four replicates. Selection parameters included: spike/plant, grain/plant and plant grain yield .The results of the first year showed superiority of the 78×90 cm distance in spikes/plant, spike length and spikelets/spike. The highest variation was found among cv. IPA99 (31±5.2, 12.8 ±1.02 cm and 22.7±1.39), respectively. These results reflected in an increase in grain /spike (76.5g ±7.0) which affected positively grain/plant. Yields of selected plants of the two cultivars were increased in the same treatment to reach 61.5 ± 7.6 and 50.7 ± 7.9 ,respectively. Seeds of some superior plants were planted in the following year according to a factorial experiment included eight combinations of cultivar distances× cultivars for evaluation and compared with original plants at seeding rates 120 and 150 kg/ha . Selection resulted in superiority of selected plants at 78×90 cm distance in yield components. Spikes/m2 were increased from 270.5 to 455.6, and grain/spike from 47.3 to 64.9 . The selected progeny gave grain yield (483.1 and 453.0 g/m2) higher than original plants (304.0 and 295.9 g/m2) for IPA99 and Abu-Ghraib3, respectively. Selection also led to homogeneity of population . Selected plant yields were increased from 302.5 g/m2 of the original plants to 523.0 g/m2 as a mean of both cvs. C.V% , S.D and SE were decreased in the selected populations . The progeny of IPA99 CV. plants which selected from 78×90cm was the most stable and highest in genetic resultant, predication criterion and combined criterion. Honeycomb selection has shown higher variation among population of the two cultivars as a result of the additive gene action that affect some characters related to yield. It was recommended to use honeycomb selection spacing (78×90 cm) for breadwheat grain yield improvement and the selection could be repeated for more generations if variations are still exist . However, higher seeding rates along with higher fertilizers rates were also recommended to test the productivity of the selected lines.