In vitro germination of Pecan (Carya illinoinensis) embryo.

Abstract. The purpose of the present study was to standardize the mediums and culture conditions for organogenesis via immature embryo culture of Pecan (Carya illinoinensis ). The immature fruits of Pecan hickory were collected 15 weeks postanthesis and, after disinfection, the immature embryos were cultured on modified DKW basal medium. Significant variations were observed between different hormones and different culture conditions. For immature embryo culture, a high frequency of plantlet was obtained in modified DKW basal medium supplemented with 1 mg l -1 BAP, 0.05 mg l -1 IBA and 2 mg l -1 GA3 and dark culture condition. In this experiment, 0.5 mg l -1 BAP and 2 mg l -1 GA3 enhanced embryo germination and shoot proliferation. Also, 0.05 mg l -1 IBA was suitable for root proliferation. In general, the percentage of immature embryos germination and shoot proliferation was higher when GA3 cold treatment and BAP were simultaneously applied, compared to those when these were applied separately. In this experiment, in the presence of different concentrations of BAP and IBA frequently calluses was induced, this calluses was green, creamy and globular form. Results indicated that the GA3 inhibited callus and root proliferation. The frequency of callus formation was lower in the dark culture condition than light culture condition. At the same time, the shoot and root direct differentiation from the cotyledons with the embryo axis and these calluses was unsuccessful

Phenotyping new rapeseed lines based on multiple traits: Application of GT and GYT biplot analyses

The selection based on multiple traits enhances the crop cultivars merit to farmers. In this regard, 19 breeding lines as well as two commercial cultivars were studied using a randomized complete block design (RCBD) with three replications in three locations during the 2020–2021 growing season. In this study, to identify the association among different traits and to select the best rapeseed lines based on multiple traits, genotype × trait (GT) and genotype × yield × trait (GYT) biplot analyses were used. The results showed that using GYT biplot is more efficient than GT biplot. Based on the GYT biplot and superiority index (SI), the breeding lines G16 and G18 were considered as superior genotypes in combination with the agronomical traits, that is, 1000-seed weight, number of seeds per pod, number of pods per plant, number of lateral branches, plant height, and pod length with seed yield, which represents a genetic gain in rapeseed breeding program. Based on seed yield combination with phenological traits (early maturity), the breeding line G15 was selected as the best one. Moreover, the line G2 was defined as the superior one in combination of seed yield with pod length. The results indicated that there is a potential for simultaneous genetic improvement of the characteristics (i.e., plant height, number of seeds per pod, early maturity) in rapeseed. Generally, the graphical method of the GYT biplot represented an efficient and practical new way to recognize superior genotypes based on multiple traits in rapeseed breeding programs

Trait profiling and genotype selection in oilseed rape using genotype by trait and genotype by yield*trait approaches

Abstract Selection and breeding for high‐yielding in oilseed rape have always been one of the leading objectives for oilseed rape breeders. This process becomes more complicated when all quantitative traits are considered in selection in addition to grain yield. In the present study, 18 oilseed rape genotypes along with 2 check cultivars (RGS003 and Dalgan) were evaluated across 16 environments (a combination of 2 years and eight locations) in the tropical climate regions of Iran during 2018–2019 and 2019–2020 cropping seasons. The experiments were conducted in a format of randomized complete block design (RCBD) with three replications. The obtained multienvironmental trial data were utilized to conduct multivariate analysis, genotype by trait (GT) biplot, and genotype by yield*trait (GYT) biplot (Breeding, Genetics and Genomics, 1:2019). The GT and GYT biplot accounted for 55.5% and 93.6% of the total variation in the first two main components. Based on multivariate analysis and GT biplot, pod numbers in plant (PNP) and plant height (PH) were chosen as two key traits in spring oilseed rape genotypes for indirect selection due to high variation, strong positive correlation with grain yield (GY), and their high representatively and discriminability in genotype selection. The mean × stability GT biplot represented G10 (SRL‐96‐17) as the superior genotype. Based on the mean × stability GYT biplot, eight above‐average genotypes were identified that took high scores in stability, high‐yielding, and all evaluated quantitative traits at the same time. Based on the superiority index of GYT data, G10 (SRL‐96‐17) and G5 (SRL‐96‐11) indicated the best yield–trait combinations profile and ranked above check cultivars and then selected as superior genotypes. Similarly, cluster analysis using the WARD method also separated eight superior genotypes. Based on the result of the present study, GT ad GYT methodologies are recommended for trait profiling and genotype selection in oilseed rape breeding projects, respectively