Peculiarities of water-yielding capacity and germination capacity formation in hybrid maize seeds upon ripening under drought conditions in the steppes of Ukraine

Abstract

The main index of seed quality is germination capacity, formation of which is largely dependent on biotic and abiotic factors influencing during ripening, harvesting and post-harvest processing. The main factors upon ripening include water-yielding capacity dynamics, dry matter accumulation, and moisture at which seeds are harvested.

In recent years, the conditions of maize growing and ripening periods have been changing significantly, which directly affects seed formation processes and seed quality. The purpose of the research was to establish peculiarities of maize hybrid ripening under different, primarily, arid conditions and to determine the moisture content at which maize seed germination capacity is formed.

Methods. The experiments were carried out at the Experimental Farm of the State Enterprise "Dnipro", which is located in the Northern steppe of Ukraine (Dnipropetrovsk region) in 2011-2013. The source material was maize hybrids bred by the Institute of Agriculture in the Steppe Zone of Ukraine NAAS, belonging to different groups of ripeness: Dneprovskiy 181 SV, Kremen 200 SV, Liubava 279 MV, Rozovskiy 311 SV. The germinative power, laboratory germination capacity and germination capacity by the “cold” method, 1000-grain weight, absolute dry weight, field germination capacity, and grain yield were determined by the conventional methods.

Results. The experiments established the peculiarities of water-yielding capacity dynamics and dry matter accumulation in maize hybrid grain in the processes of its ripening and drying. It was revealed that upon climatic changes towards aridity maize hybrid seed ripening is accompanied by the intensive water-yielding of 0.6-1.92 % per day, depending on hybrids, which is significantly higher as compared to the long-term data. The major dry matter accumulation is over when the moisture content is 22-30 %, but a dry matter loss may occur due to seed moisturizing and intense respiration.

On fast water-yielding the nature of germination capacity formation in maize hybrid seeds changes. Seeds of the hybrids investigated achieve the standard germination capacity (not less than 92 % in accordance with the National Standards of Ukraine 4138) at the moisture content of 47-53 %; the germinative power, high field germination capacity and performance are reached at the moisture content of 32-40 %, depending on a ripeness group of hybrids.

Conclusions. The findings are of practical value; they should be applied upon determining the optimal timing of early harvesting and post-processing of maize hybrids. Fuel consumption for drying seeds with high moisture content is compensated by a rise in seed yield, because when harvesting and processing are late, its loss in the form of grain waste shelled from ears increases.