Search

Safflower is an underutilized and minor oilseed crop that received less attention from the scientific community comparedto other oilseed crops like soybean and sunflower. Exploring the genetic basis associated with agronomic traits is crucial for markerassisted breeding of safflower. A genome-wide association study was conducted using a total of 12,232 DArTseq markers to identifythe marker-trait association for important agronomic traits in an international safflower panel derived from 26 different geographicalcountries of the world. Statistically significant genotypic effects (p< 0.05) were observed across mean data of both locations (Pakistanand Turkey). Moderate to high heritability estimates were observed for the studied traits. Studied material showed higher performancefor all traits except seeds per capitulum in Pakistan compared to Turkey. Phenotypic diversity for important agronomic traits, such asplant height (60.08 to 121.48 cm), capitula per plant (8.7 to 80.4), seeds per capitulum (15 to 42.05), and seed yield per plant (4.85 to51.02 g), was illustrated. Seed yield per plant showed a highly significant and positive correlation with capitula per plant (0.4985***).Constellation plot analysis resulted in four groups, i.e. A, B, C, and D. Genotyping by sequencing resulted in 12,232 DArTseq markersbeing used for the investigation of marker-trait association through mixed linear model (Q + K) approach. DArT-38077549 showedsignificant association with capitula per plant, while two markers (DArT-22763576, DArT-22763253) were associated with plant height.A total of two markers (DArT-38079422, DArT-100043360) were associated with seeds per capitulum. A total of five DArTseq markersshowed significant association with seed yield per plant and maximum variation was resulted by DArT-100004992. The results of thisstudy provide a new insight to understand the genetic basis associated with agronomic traits in safflower. We envisage that significantmarkers identified through this investigation may be applicable in future safflower marker-assisted breeding programs.

The salt stress tolerance of 19 hybrid maize (Zea mays L.) varieties was tested in nutrient solution during the early growth stage under controlled environmental conditions. For the salt stress treatment, sodium chloride (NaCl) was applied to nutrient solution at a concentration of 250 mM for 6 days before the harvest. Plants were harvested after 17 days of growth and analyzed for shoot and root dry matter production, severity of leaf damage (necrotic patches on older leaves), and the concentrations of potassium (K), sodium (Na) and calcium (Ca) in the roots and shoots. The varieties differed greatly in their response to the NaCl treatment. The development time and severity of leaf symptoms caused by 250 mM NaCl were varied markedly among the varieties. Based on the severity of leaf symptoms, the varieties Maverik and C.7993 were classified as the most tolerant and sensitive varieties, respectively. The decreases in the shoot dry matter production as a consequence of the NaCl treatment were higher than the decreases in root growth. There was also a marked genotypic variation in concentrations of K, Ca and Na in roots and particularly in shoots. The higher salt tolerance in maize varieties based on the severity of leaf symptoms was associated with significantly lower Na concentrations in shoots. The K/Na and Ca/Na ratios were significantly greater in most of the tolerant varieties. The most sensitive variety, C.7993, contained a 4-fold greater Na concentration in shoots than the most tolerant variety, Maverik. The varieties RX.9292 and MF.714 also contained very high Na in shoots and showed severe toxicity symptoms on leaves. Besides Maverik, P.3394 and P.3223, with their low shoot Na concentrations, could also be considered tolerant varieties. Under salt treatment significant correlations were found between K/Na ratios and shoot dry matter production (r = 0.541***), K/Na ratios and leaf damage (r = –0.411***), and Ca/Na ratios and shoot dry matter production (r = 0.444***). The results indicate the existence of a large genotypic variation in tolerance to NaCl toxicity in maize that should be exploited in breeding programs aiming to develop maize varieties with high NaCl tolerance during the early growth stages. Among the ions measured, shoot Na concentration was a reliable screening parameter in ranking varieties for their tolerance to salt stress.