In 2011-2017, the competitive testing breeding units of soft winter wheat selected at the Bila Tserkva Research Selection Station of the Institute of Bioenergetic Crops and Sugar Beet of NAAS by hybridizing various ecotypes were examined.
The aim of the research was to determine the reaction norm and parameters of adaptability by the number of grains in the spike ear under changing growing environment in selection winter wheat numbers. Of equal importance was to establish the correlation of the ear grain productivity and the yield structure elements.
Hydrothermal conditions in the research years were contrasting and significantly influenced the growth and development of wheat plants during ontogenesis.
The research revealed a direct correlation between the number of grains in the spike and the grain yield leveled as a strong one (r = 0.702 ... 0.866) in 2011 and 2012 and as a significant (r = 0.668) in the most unfavorable 2013. The reduced correlation relationships are indicative of the extremely important importance of the grain production in the spike in soft winter wheat yield formation under conditions of the Forest-steppe of Ukraine.
We have established a direct close correlation between the number of grains in the spike and the number of grains in the crop, between the head ear grain weight and the crop weight, crop aboveground weight, main stem weight and the spike weight.
On average for three years, breeding numbers 24 KS (42.6 pcs.) and 54 KS (40.7 pcs.) had significantly higher grain yields in the spike than that of is the best standard of Bila Tserkva semidwarf (35.6 pcs) .
On average for the experiment coefficient of variation (13.9 %), its variability was 1.0–28.7 %, indicating a different reaction of the tested genotypes to the environmental conditions by the number of grains from the spike. Insignificant variation of the spike grain productivity (0.6–4.9 pcs) and low variation coefficients (V = 1.0–6.6 %) are indicated in the selection numbers 26 KS, 22 KS and 42 KS. In this case, genotypes 22 KS and 42 KS had higher than the standard and average for the experiment number of grains in the spike.
The results of the dispersion analysis indicate that the interaction of genotype and the year conditions factors had the greatest impact (53.96 %) on the variability of grains number in the spike. At the same time, the share of variability predermined by the genotype influenced the spike grains formation by 31.02 %, and the conditions of the year influenced only by 7.90 %.
Indicator of homeostatic standards (Hom = 158.97-347.13) exceeded the three breeding numbers: 26 KS (Hom = 2972.19), 22 KS (Hom = 724.23) and 42 KS (Hom = 558.67). By the breeding value the standards (Sc = 21.83–27.94) were dominated by the following: 22 KS (Sc = 34.27), 42 KS (Sc = 32.49), 54 KS (Sc = 32.20), 24 KS (Sc = 30.62), 26 KS (Sc = 29.54), 8 KS (Sc = 28.76) and 29 KS (Sc = 28.26).
High indicators of ZAZ by the number of grains from the spike as compared with the standards (ZAZ = 52.46) were typical of the following breeding numbers 24 KS (ZAZ = 67.99), 54 KS (ZAZ = 58.29), 22 KS (ZAZ = 54.69), 44 KS (ZAZ = 53.99) and 42 KS (ZAZ = 52.86).
The genotype breeding value indicator by the number of grains in the spike, exceeded the standard variety of the Forest-steppe Pearl (GBV = 22,10) for their breeding value: numbers 22 KS (GBV = 31.44), 26 KS (GBV = 29.00), 42 KS (GBV = 28.60) and 54 KSCOP (GBV = 22.69).
The breeding number 22 KS (steppe ecotype / US) is the first in the variety adaptability rate. Breeding numbers 42 KS, 54 KS and 24 KS, which optimally combined indicators of the grains number in the spike and adaptability parameters rate from the second to fourth in the varieties adaptability rate.
Conclusions and further research prospects. 1. Grains number in the spike has a significant impact on the winter wheat spike productivity formation under conditions of the Forest-steppe of Ukraine.
2. Detection of correlation between quantitative signs engaged in yields formation enables to set the model parameters for further genotypes in future varieties.
3. The dispersion analysis has established that the variability of the grains number in the spike was mostly conditioned (53.96 %) by the interaction of factors of the genotype and the year conditions. At the same time, the share of variability predetermined by the genotype was 31.02 %, and the effect of the year was only 7.90 %.
4. Breeding numbers 22 KS (steppe ecotype / USA), 42 KS (steppe ecotype / forest-steppe ecotype) and 54 KS (forest-steppe ecotype / forest-steppe ecotype) hold high positions in the variety adaptability rate by the grains number in the spike.
We included the soft winter wheat breeding numbers 22 KS, 42 KS and 54 KS with the optimal combination of the grains number in the spike and the parameters of plasticity and stability, allocated on the basis of the research results into further selective work for setting the source material and varieties with a high level of productivity and adaptability to the conditions of the Forest-steppe of Ukraine.
Key words: soft winter wheat, breeding numbers, ecotypes, number of grains, spike, correlation relationships, adaptability parameters, adaptation rating.
