Сельскохозяйственная биология, 2010, № 3, с. 59-62.

УДК 633.111.1:631.522/.524:581.151:57.04

REACTION OF HYBRID POPULATIONS OF SPRING SOFT WHEAT ON SELECTION OF PRODUCTIVITY AND CORN QUALITY AT CONTRASTING AMOUNT OF PRECIPITATION AS A BACKGROUND

V.M. Bebyakin, I.A. Osyka

The authors have the breeding value (mass of corn per plant, full-size corn mass, parameters of SDS-sedimentation and gluten content) in high-quality varieties of summer soft wheat on progeny in a system of the one-tester crossings. The hybrid populations reaction on the breeding of plant productivity and corn quality and also their realized hereditability was shown.

Key words: response of hybrid populations to selection, progenies, quality indicators, heritability.

Creating the local gene pool with high technological properties of corn is one of main conditions for breeding intensification (1). This task requires clarification of some approaches to the theory of selection the best genotypes and their identification in typical complete populations (2-4).

The purpose of this study was the evaluation of  wheat hybrid populations’ response to selection in F₂ and F₃ by productivity and corn quality indicators.

Methods. The field experiments were carried out in 2004-2005 (breeding crops rotation field of SRI of Agriculture in South-East, Saratov). In one-tester scheme crosses, the varieties Tulaykovskaya 5 (T 5), Tulaykovskaya zolotistaya (Tz), Albidum 42/98 (Al 42/98) and SKENT 3 (SK 3) were used as maternal forms and the line SFR 195-11 -05 (SFR 195) as a tester; SFR 195 is resistant to leaf rust but it has a low quality grain with high gluten content. F₂ and F₃ hybrids (the account of plant progeny generations) were grown together with plants of parental varieties in 3-linear plots arranged by the method of frequent standards.

In the period of field experiments (2004-2005), weather conditions were contrasting: in the first year, precipitation during corn formation and ripening amounted to 88,0 mm (173% of normal), in the second year - 19.8 mm (39% of normal), while air temperature corresponded to multiyear averages (96,7-100,9% of climatic norm).

A full-scale (natural) grain weight was estimated using the micromodification method of Siberian SRI of Agriculture (5), SDS-sedimentation rate - under the method of V.M. Bebyakin and M.V. Bountina (6). Gluten content and quality were determined according to GOST (with decreasing a flour sample to 10 r). Variance analysis was performed using the program for non-repeated experiments with frequent standards and data correction to moving average. The populations’ response to selection (R) with different intensity (> Хп, i20, i10) in the system of two generations were determined upon the difference between the indicator average in the entire population (X) and the average value in the selected part of previous generation progenies. Realized (actual) heritability was evaluated by the formula: h2 = R / S, where R - selection shift, S - selection differential (the difference between phenotypic average in the selected group of progenies and the average in total parental generation before the selection).

Results. The average values of parameters in the selected part of hybrid progenies (Table 1) regularly increased with raising the intensity of natural selection (except IDC-1 index measured on the gluten strain meter IDC-1 (Russia), which showed a negative value). The greatest intensity of indicators (considering positive/negative sign of values) was detected at the selection in populations of 10% (i10) progenies. Note: the selection was performed upon the grain formed in rainy year 2004. The grain formed in period of rain shortage (2005) has shown the sharply declined averages of  productivity parameters in both the whole population and in progenies selected in preceding generation. A natural grain weight decreased as well, or less often it remained unchanged. 

Under the draught conditions, SDS-sedimentation rate in most cases was higher in all progenies of the population (Хп) and at the selection of progenies with largest sediment Хп; the smaller values were observed when the selection of 20 and 10% best families (see Table 1. ). Gluten content in flour varied unequally in different populations with change of generation and environmental conditions. As a rule, F3 hybrids (Tulaykovskaya 5 x SFR 195-11-05) and F₃ (Tulaykovskaya zolotistaya x SFR 195-11-05) demonstrated the higher gluten content than the preceding generation hybrids (F₂), and the less values were detected  in populations with the participation of Albidum 42/98 and SKENT 3 (see Table. 1). Gluten quality was significantly better under precipitation deficit (2005) compared to that in the rainy year. So, the change of generations and contrasting weather conditions during grain formation and ripening cause different effects on quantitative values of quality indicators, which influences the effectiveness of selection.

The response of hybrid populations to selection is an important characteristic for evaluation the varieties upon their progeny. The value of selection differential (S) under different intensities of selection was sufficiently large for all the studied parameters. Nevertheless, populations’ response to selection (R) for all the parameters except IDC-1 index, was rather small or did not appear at all (Table 2). Moreover, the studied progenies best in a certain criterion were often becoming among the worst after replanting. Thus, when the selection of best progenies in F₂ (from a plant), there’s no guarantee to obtain positive results in following generation (F3) by all the parameters except IDC-1 index, if F₂ and F₃ were grown in vegetation seasons with contrasting weather conditions.

In the context of experiment, the realized heritability of parameters (h2) was low in all the variants or did not manifest itself at all. The only exception - gluten quality: the selection on IDC-1 index can be quite effective in the populations of Albidum 42/98 x SFR 195-11-05 and SKENT 3 x SFR 195-11-05) (Table 3). The selection of progenies by SDS-sedimentation rate exceeding the average for a population (X) allowed to expect positive results in F₃ (Albidum 42/98 x SFR 195-11-05) as well, by gluten content in flour - in F₃ (Tulaykovskaya 5 x SFR 195-11-05). A high heritability of gluten content was revealed when the selection of 20% best progenies in the F₂ population (Albidum 42/98 x SFR 195-11-05).

Thus, the response of summer wheat hybrid populations (R) to the selection by grain weight per plant, natural grain weight, SDS-sedimentation rate and gluten content in F₂-F₃ (from a plant) in years with contrasting  amount of precipitation, was very small (from positive to negative values). The shift in gluten quality (IDC-1 index) was quite significant (1,3-7,1 units) in three of the four studied populations at all applied intensities of selection (> Xn, i20, i10). The only parameter - IDC-1 index - showed a stable realized heritability at different intensity of selection.

REFERENCES

1. Б е б я к и н  В.М.,  О с ы к а  И.А. Продуктивность и качество зерна гибридов яровой пшеницы при однотестерных скрещиваниях. В сб.: Современные проблемы почвозащитного земледелия и пути повышения устойчивости зернового производства в степных регионах. Шортанды, 2006, ч. 2: 347-351.
2. Б е б я к и н  В.М.,  О с ы к а  И.А.,  К и б к а л о  И.А. Урожайность гибридов яровой мягкой пшеницы и ее изменчивость в популяциях. В сб.: Вопросы биологии, экологии, химии и методики обучения. Саратов, 2006, вып. 9: 21-25.
3. О с ы к а  И.А. Качество клейковины у гибридов F2 яровой мягкой пшеницы и их родительских форм в системе однотестерных скрещиваний. В сб.: Молодые ученые — агропромышленному комплексу Поволжского региона. Саратов, 2006, вып. 2: 124-126.
4. Б е б я к и н  В.М.,  О с ы к а  И.А.,  К у л а г и н а  Т.В. Оценка высококачественных сортов яровой мягкой пшеницы по потомству. Докл. РАСХН, 2007, 3: 11-13.
5. Оценка качества зерна: Справочник /Сост. И.И. Василенко, В.И. Комаров. М., 1987.
6. Б е б я к и н  В.М.,  Б у н т и н а  М.В. Эффективность оценки качества зерна яровой мягкой пшеницы по SDS-тесту. Вест. с.-х. науки, 1991, 1: 66-70.