Effects of Planting Date, Genotype, and Their Interactions on Sunflower Yield

Abstract

Sunflower (Helianthus annuus L.) yields are strongly reduced by late sowing dates. The objectives of this study were to investigate the physiological bases of the sowing date (S), genotype (G), and genotype × sowing date (G × S) interaction effects on sunflower yield and contribute to development of ideotype‐based selection strategies for improving yield at late plantings. Nine differentially adapted hybrids were evaluated during two seasons at normal and late planting dates at Venado Tuerto, Argentina, by means of the framework that defines oil yield as the product of grain number and weight and oil concentration. Sowing date was the major source of variation for oil yield. The G × S interaction, in turn, accounted for a portion of the total variability four times higher than the contribution of G. The S and G × S interaction effects on grain number were mostly determined by grain set in the central portion of the capitulum. Duration of grain filling was the main determinant of the S and G × S interaction effects on grain weight and grain oil concentration. Variation in grain oil concentration between sowing dates was largely due to changes in kernel oil proportion, rather than changes in kernel percentage. Relative changes in rate of grain filling and kernel percentage also contributed to the observed G × S interactions for grain weight and oil concentration, respectively. Although some degree of compensation among oil yield components underlie the observed G × S interactions, it was found that seed set in the central portion of the head can be used as an indicator of adaptation to late planting dates.

Seed yield, head characteristics and oil content in sunflower varieties as influenced by seeds from single and multiple headed plants under humid tropical conditions

“…Head diameter is an important trait that has been reported to have positive direct effect on seed yield (Machikowa & Saetang, ) and it varies among varieties and hybrids based on their different genetic potential (Nasreen et al , ; Khan et al , ). The range of 429–639 achene per head recorded on single headed plants in our study is grossly below the range of 5752–6550 achene per head produced by hybrids in Argentina (de la Vega & Hall, 2002 b ) and 1148–1509 achene per head in Pakistan (Ali et al , ). This sharp contrast indicates that irrespective of the location, sunflower hybrids are more productive than the open pollinated or synthetic varieties since the hybrid will maximise the phenomenon of heterosis (hybrid vigour).…”

“…The genetic basis of high morphological variability resulting in branching of sunflower is not fully understood (Sandu et al , ). Seed oil content which is an important selection criterion in the improvement of sunflower varies among cultivars (Lopez et al , ; Leon et al , ; Chigeza et al , ) and is affected by the amount of solar radiation intercepted by the cultivar (Dosio et al , ; Aguirrezábal et al , ), temperature (Rondanini et al , ; Khan et al ., ), sowing date, genotype, and their interactions (de la Vega & Hall, 2002 a , b ; Aslam et al , ; Lawal et al , ), plant density (Barros et al , ; Zarea et al , ) and foliar application of molybdenum at V‐4, four developed leaves stage (Skarpa et al , ). Oil content in sunflower is a function of the maternal plant genotype and not by kernel genotype (Thompson et al , ).…”

Genotype by environment interaction in sunflower (Helianthus annus L.) to optimize trial network efficiency

“…The mega-environments were defined by management practices such as sowing date and differences between years, mainly explained by meteorological conditions, rainfall and temperature, in flowering time. Our results coincide with other studies that analyzed the conformation of mega-environments in sunflower (de la Vega & Hall, 2002;Balalic et al, 2012).…”

“…Late sowing dates are related to higher temperatures during the growing season, which generate excessive growth of stems (Beard & Geng, 1982) and a reduction of time destined to flowering (Andrade, 1995). Exposure to higher temperatures and solar radiation negatively affect the grain filling phase (Andrade, 1995;Bange et al, 1997;de la Vega et al, 2001;de la Vega & Hall, 2002). In particular, the grain filling phase has been reported to be highly variable between years, locations and sowing dates due to the variations of temperature and solar radiation (Izquierdo et al, 2009).…”

Produção do girassol e teor de óleo nas sementes em diferentes épocas de semeadura no Centro-Sul do Paraná

“…Da mesma forma, VEGA & HALL (2002) concluíram que a produção de aquênios diminuiu acentuadamente quando a semeadura ocorreu em épocas tardias na Argentina.…”