Effect of planting date on some agronomic traits of four oat lines (Avena sativa) in Birjand

Oat (Avena sativa L.) is a plant belonging to the Poaceae family and adapted to cold and moderate weather conditions. Avena genus includes annual herbaceous plants with economic and medicinal importance. Among the various aspects of agricultural management, choosing the right cultivar and planting date is the most noticeable, because even in similar climates and the same planting date, there is a great difference in the performance of different cultivars and genotypes. Due to the fact that high-yielding oat line and its appropriate planting date have not been introduced for Birjand region, this research was conducted with the aim of investigating the effect of planting date on some agronomic traits of four cultivated oat lines in Birjand.

In order to investigate the possibility of oat crop genotypes planting in Birjand, a factorial experiment based on a randomized complete block design with three replications was conducted in 2013 at the research farm of the Faculty of Agriculture, Birjand University. The two factors studied included four cultivated oat lines (A5, L2, L7 and bare oats) and three sowing dates (October 24, November 10 and November 26). In this study, traits such as plant height, inflorescence length, number of tillers per plant, number of days to emergence, stem elongation, ear emergence and to maturity, number of ear per square meter, number of seeds per ear, 1000 seed weight, grain yield, biomass yield, harvest index, seed protein percentage and protein yield were studied.

The effect of line on the studied traits except for the number of tillers per plant, number of ear per square meter and biological yield was significant. L7 line with 7003 and 1061 kg.ha-1 had the highest seed and protein yield, respectively. The effect of planting date on inflorescence length, number of seeds per panicle, seed yield, harvest index and protein yield were not significant. Delay in planting, although it caused a delay in emergence and especially a delay in the beginning of tillering, accelerated the reproductive growth of the plant. So that on the date of planting November 26 compared to October 24, ripening occurred more than two weeks earlier. The colder weather on the planting date of November 26, delayed the germination of the seeds. Also, delay in planting from October 24 to November 26 reduces plant height (8.6%), number of spikes per square meter (21.2%), biomass yield (9.6%) and increases the number of tillers per plant (35%). By changing the planting date, many environmental conditions for production will change. Following these changes, some plant characteristics effective in seed performance, including the production of flower buds, which are directly influenced by day length and day and night temperature, change in the direction of increasing or decreasing seed yield. At an earlier planting date, the length of the oat growth period increases and this plant uses more light and nutrients in the soil and therefore its height increases. The interaction effect of planting date and line was significant only on the number of days to stem elongation, number of days to maturity, 1000-seed weight and seed protein percentage. The highest percentage of seed protein was related to the bare line in planting date of November 26 and the lowest in A5 line in planting date of October 24. It seems that in earlier planting dates, the plant had more opportunity to use nutrients, especially nitrogen, while in later planting dates, due to the short growth period of the plant, there was no such possibility. As a result, seed protein has increased in earlier planting dates.

Based on the results of this experiment, L7 line can be used on November 23rd to have the highest grain yield, biomass yield and protein yield for Birjand region.