Planting Date Influence on Soybean Agronomic Traits and Seed Composition in Modified Fatty Acid Breeding Lines

Abstract

A primary focus for soybean [Glycine max (L.) Merr.] breeders recently has been the development of cultivars with improved oil qualities such as reduced palmitic acid (16:0) and linolenic acid (18:3). A backcross breeding program was used to develop five low 16:0, two low 16:0 + 18:3, and one low 18:3 modified fatty acid breeding lines (MFALs). Research objectives were (i) to determine planting date effects on fatty acid content in the eight MFALs and (ii) to compare the MFALs to parental cultivars for seed composition and agronomic traits. The eight MFALs and four control cultivars were evaluated at two planting dates at Clemson, SC, in 2001, 2003, and 2004. Planting dates were chosen to simulate full season and double crop planting dates for South Carolina soybean production. Agronomic traits including seed yield, plant height, lodging, maturity date, seed size, and seed quality were measured, and seeds were analyzed for protein, oil, and fatty acid levels. Planting date had a significant effect on all agronomic variables, as well as on protein, oil, and palmitic and linolenic acid. There was a decrease in palmitic acid at the late planting date, while the early planting date resulted in a decrease in linolenic acid levels. The effect of genotype was significant for all agronomic and seed composition variables measured when averaged across planting dates. It appears that planting date may be manipulated to reduce palmitic or linolenic acid of MFALs, although the extent of the reduction varies with genotype.

Water Deficit Effect on the Relationship between Temperature during the Seed Fill Period and Soybean Seed Oil and Protein Concentrations

“…average mean temperature during soybean development under fi eld trials. In a recent fi eld study (Ray et al, 2008), it was demonstrated that oil and protein concentrations increased at early planting dates exposed to increased mean daily temperatures during seed formation. Response of oil + protein concentration to Tm R5R7 was linear and positive (Table 5), with a slope of 0.48% °C −1 .…”

“…Moreover, Naeve and Huerd (2008) found a significant positive linear response of oil + protein to temperature during the seed-fi lling period in farm-fi eld samples in Minnesota. In a recent fi eld study (Ray et al, 2008), it was demonstrated that oil and protein concentrations increased at early planting dates exposed to increased mean daily temperatures during seed formation. Gibson and Mullen (1996) found that oil + protein concentration increased at low rates within the range between 25 and 32.5°C, which is a higher range than observed in the present study.…”

“…Soybean seed composition is known to be aff ected by environmental factors (Ray et al, 2008), especially during the seed-fi ll period when oil and protein dry mass accumulation occurs (Wilson, 2004). Multienvironment trials could be useful to assess environmental eff ects on oil and protein composition under fi eld conditions.…”

Biometric analysis of protein and oil contents of soybean genotypes in different environments

“…The selection for high protein or oil content should be preceded by analyses for genotype x environment interaction (GxE), since seed composition is affected by environmental factors, such as temperature, water availability, and nitrogen supply, especially during the seed-filling period (Ray et al, 2008). In general, supplemental nitrogen during seed filling increases seed protein content, whereas water stress and high temperatures reduce both protein and oil contents in the seeds.…”

Response of Some Soybean Genotypes to Planting Date and Plant Density

“…Seed yield of soybean cultivars decreased with delayed sowing. They also found that higher yields were associated with more pods and higher seed weight/plant as well as higher weight of 100 seeds (Amir et al(2000), Hassan et al (2002), Mohamed et al (2002), Ray et al(2008), Futuless and Ngodi (2010) Morsy (2010) and Mostafa Azhar (2011).…”