Yield and yield quality of confectionary sunflower varieties depending on plant populations

Influence of the different plant populations (20, 30, 40, and 50 ths plants per ha) on yield and yield quality of confectionary sunflower varieties SPK, Jinn, Lakomka and Krupnyak was studied on leached chernozem (Krasnodar region) in 2014-2015. Weather conditions in May - August in 2014-2015 were characterized with a lack of soil water defi-ciency in before-sowing period (April), sufficient precipitation amount in May - June 204, and heavy rains in 2015, high daily average and average maximal temperature at low relative air humidity. During flowering and seed filling the daily average air temperature exceeded the climatic norm: in June - on 1.6-2.6оС, in July - on 2.0-2.2 and August - on 3.6-4.4 оС at average maximal air temperature in July - August 31.4-34.0 оС and и relative air humidity in these months 56-58 and 43-44%, respectively. The weather conditions having been during vegetative pe-riod of confectionary sunflower varieties allowed receiving high yield and revealing dependence to obtain seeds of different fractions with required commercial qualities. The highest yield was recorded at plant population 40-50 ths plant per ha (3.11-3.19 t per ha). Max yield of seed fraction 38+ is reached at production of studied varieties with plant population 25- 35 ths per ha (2.73-2.74 t per ha). Under increase of plant population from 20 to 40-50 ths per ha oil content in seeds of varieties increased on 1.5-1.8%. Accounting seed yield of fraction 38+ and oil content in seeds, the greatest oil yield (up to 1.07 t per ha in average) was reached at production of studied confectionary sunflower varieties with plant population 30- 35 ths per ha. Enlarging of plant population from 20 to 50 ths per ha leads to reducing of head diameter on 30.0-34.2%, amount of filled seeds in a head on 39.7-51.2%, 1000 seed weight on 21.5-29.7%, seed huskiness on 2.1-3.3% and to increase of volume seed weight 3.2-5.6%.