Peculiarities of filling and yield formation in modern varieties of durum spring wheat

Abstract

Cultivation of any crop and achievement of a high top-quality yield are impossible without the knowledge of biological characteristics of the plant and its organs, the most important of which is grain.

The aim and tasks of the study. The aim was to identify the dynamics of grain filling, to establish ecotypic affiliation of modern accessories durum spring wheat, to find correlation between yield capacity and 1000-grain weight. 

Materials and methods. The investigations were carried out in stationary fallow-grain row-crop rotation by the split plot method taking into account all requirements of the field experimentation methodology in the Laboratory of Plant Production and Variety Studies of the Plant Production Institute nd. a VYa Yuriev of NAAS in 2013-2015. Predecessor was sugar beet on without fertilizer (control) and with mineral fertilizers at the dose of N₆₀P₆₀K₆₀after 30 t/ha of manure. Durum spring wheat grain filling was determined according to the techniques of determination of agro-ecological plasticity of varieties.

Results and discussion. During the growing season of durum spring wheat in 2013-2015, the yearly hydrothermal coefficient was 0.57, 1.44 and 1.15. Thus, the growing season of 2014 was well-moistened (HTC = 1.44) and turned out to be the most favorable for the development of durum spring wheat, and the growing season of 2013 was dry and unfavorable (HTC was 0.57). The vegetation period in 2015 was optimal in terms of moisture level – HTC = 1.15.

All the test durum spring wheat varieties were found to clearly belong to the forest-steppe ecotype, since the maximum amount of plastic substances in grain was accumulated in the milky stage (grain moisture 69-50%), regardless of nutrition. The gain in 1000-grain weight during this period on average across the varieties was 23.7 gwithout fertilizers and 21.4 gwith mineral fertilizers at the dose of N₆₀P₆₀K₆₀after 30 t/ha of manure. Variety ‘Spadschina’ accumulated the highest amount of dry matter in this period without fertilizers -26.2 g; the intensity of grain filling was1.74 g / day. On fertilizer background, variety ‘Isolda’  accumulated the highest amount of dry matter -25.7 g; the filling intensity was 183 g / day.

The study demonstrated that as 1000-grain weight increased after application of mineral fertilizers, the yield capacity of durum spring wheat varieties also increased. For example, over the study years on mineral fertilizer-free background, the average yield capacity across the varieties was 2.60 t / ha, and when mineral fertilizers were added, it increased by 0.85 t / ha and was 3.45 t / ha. The maximum 1000-grain weight without fertilizers was recorded for variety ‘Spadschina’ (45.7 g); and on fertilizer background – for variety ‘Zhizel’ (51.1 g), with the yield capacity of 2.66 t / ha and 3.44 t / ha for these varieties, respectively.

There were average negative correlations with r = -0.48 and r = -0.68 between 1000-grain weight and yield capacity for mineral nutrition backgrounds, respectively.

Conclusions. The study established that all the durum spring wheat varieties belonged to the forest-steppe ecotype. The varieties accumulated the largest amounts of dry matter in the phase of milk ripeness (21.4-26.2 g), depending on a variety and mineral nutrition.

The maximum 1000-grain weight without fertilizers was recorded for variety ‘Spadschina’ (45.7 g); and with N₆₀P₆₀K₆₀ application – for variety ‘Zhizel’ (51.1 g). The yield capacity, like 1000-grain weight, increased on average across the varieties by 0.85 t / ha after fertilization. No significant difference between varieties was seen.