Influence of genotype and environment on oil and protein concentrations of canola (Brassica napus L.) grown across southern Australia

Abstract

Improvement of oil and protein concentrations is a primary breeding objective for canola (Brassica napus L.) grown in the low rainfall areas across southern Australia. This study investigates the relative influences of genotype and environment on the relationship between seed oil concentration and protein concentration of meal, and between seed components. The study also estimates the magnitude of genetic and genotype × environment variances in oil and protein concentrations in a set of interstate field evaluation experiments of genotypes with early and mid-season maturity conducted across southern Australia in 1996 and 1997.The oil concentration of seed ranged from 36 to 46% across maturity groups, locations, and years. The range of protein concentration of meal was 30–46%. Environment had a much larger impact than genotype on oil concentration of seed and protein concentration of meal. Several genotypes in this study had higher concentrations of oil in the seed and protein in the meal than the commercial cultivars used as controls. Significant (P < 0.05) genetic variance (σg2) and significant genotype × year × location interaction (σgyl2) was present in these 2 quality traits. However, the variance components for the interaction of genotype with location (σgl2) and with year (σgy2) were not significant (P > 0.05), indicating that ranking of genotypes remained constant across locations averaged over many years and across years averaged over many locations, respectively. A significant negative correlation (r�=�–0.73) between seed oil concentration and protein concentration of meal was observed across locations in 1997. Among the genotypes tested, there was no genetic correlation between these 2 traits, suggesting that seed oil concentration and protein concentration of meal can be increased simultaneously by selection. Increase in oil concentration of seed and protein concentration of meal was at the expense of seed residue.

Productivity, Nutrient Uptake and Profitability of Sweet Sorghum -Mustard Cropping System under Different Levels of Nitrogen

“…The highest productivity of systems due to application of nitrogen is owing to greater availability of nitrogen to the plants which improved growth attributes through higher net photosynthesis by rapid CO2 which in turn resulted in increased absorption nutrients including nitrogen from the soil. These findings were supported by several researchers who revealed that nitrogen application improved plant growth and yield attributes in sweet sorghum [Delacy et al, 2010& Poornima et al, 2008 and mustard (Si et al, 2003) System under hybrid 'CSH 22 SS' recorded the higher equivalent yield (5.45 t ha -1 ) compared to SSV 84 (4.82 t ha -1 ) and RSSV 9 (4.72 t ha -1 ). (Table 3 and Fig 2,b).…”

Genetic analysis on oil content in rapeseed (Brassica napus L.)

“…SE standard error Difference = C -R *, ** Represent significant differences at the 0.05 and 0.01 probability level, respectively environmental factors (Pai and Kumar 1991;Si et al 2003). A large difference in the oil content of parental materials is necessary for the genetic basis of this trait to be accurately determined.…”

“…However, until now there is no recognized model for the genetics of oil content in B. napus. It is commonly considered that oil content in B. napus is a complex quantitative trait controlled by multiple genes and is influenced by various environmental factors (Si et al 2003). Diverse models to explain the genetics of oil content in B. napus have been confounded by different methods of oil analysis.…”

Identification of QTL for oil content, seed yield, and flowering time in oilseed rape (Brassica napus)

“…Factors such as plant growth environment (Si et al 2003), seed color (Rahman et al 2001), and erucic acid content (Cheung and Landry 1998) all contribute to the variation in oil content. Ecke et al (1995) identified three QTL for seed oil content in B. napus; of these, two showed a close association in location to two erucic acid genes.…”