Genetic diversity, population structure and marker-trait associations in Indian kale (Brassica oleracea L. gp. acephala) using cross-species microsatellite markers.

Kale is known for its exceptional nourishing and functional benefits to human body. However, it is an understudied species from genomic as well as agronomic aspects. It is important to characterize niche kale germplasms around the world to systematically conserve and utilize its genetic variability, especially for commercial traits in the interest of growers, consumers and industry. With this view, genomic and phenotypic characterizations of 62 Kashmiri kale accessions including popular landraces were done to estimate and partition genetic diversity, understand trait relationships, develop population structure and divulge marker-trait associations of economic significance. Sixty-six cross species microsatellite (SSR) markers within Brassica genus amplified 269 alleles in the germplasm. Their polymorphic information content (PIC) ranged from 0.00078 to 0.953 with an average of 0.407. The population structure analysis and neighbour joining tree clustering categorized the germplasm into three sub-populations. AMOVA revealed more within-population variance (67.73 %) than among-populations (32.27 %) variance. The principal component analysis (PCA) involving 24 agronomical traits revealed seven PCs (PC1 to PC7) having Eigen values more than 1, which explained a cumulative variation of 69.21 %. Association mapping with respect to these 24 agronomical traits using mixed linear model and general linear model revealed six overlapping significant marker-trait relationships with five being significant at probability value of 0.001/0.0001. The highly significant associations of two SSRs with economically important traits (siliqua length and seed weight) significantly correlated/related with leaf yield and seed yield were revealed for their possible utilization in marker assisted breeding for higher leaf and seed yields.

Functional Response of Four Syrphid Predators Associated With Green Apple Aphid (Hemiptera: Aphididae) in Laboratory.

Aphis pomi De Geer, the green apple aphid, is an economic pest of apple and other rosaceae throughout the world. In the present study, functional responses of the syrphids Episyrphus balteatus De Geer, Eristalis tenax(L.), Eristalis interruptus (Poda), and Sphaerophoria scripta (L.), to A. pomi were studied under laboratory conditions to determine their relative predatory potential. The second- and third-instar larvae of the predators were exposed to increasing densities of similar-sized A. pomi nymphs in Petri dishes. Ep. balteatus was found to possess the highest consumption rate followed by Er. tenax, Er. interruptus, and S. scripta. All predator species and stages exhibited a Type II functional response. The coefficients of attack rate and handling time showed an insignificant variation between species and preying stages, suggesting equal potential of the four syrphid species to regulate A. pomi colonies.

Qualitative and quantitative prey requirements of two aphidophagous coccinellids, Adalia tetraspilota and Hippodamia variegata.

The suitability of two prey species, Aphis pomi De Geer (Hemiptera: Aphididae) and Brevicoryne brassicae (L.), for two generalist aphidophagous coccinellids, Adalia tetraspilota (Hope) (Coleoptera: Coccinellidae) and Hippodamia variegata (Goeze), at various abundance levels was investigated under laboratory conditions. While both A. pomi and B. brassicae were found to be suitable, the predators performed better when feeding upon B. brassicae. The prey densities affected the developmental parameters of the two predators appreciably. Optimal growth and development was noted in the prey density range of 40-80 aphids per day per predator. Both species and abundance levels of prey significantly affected the larval period of the two predators. Appreciable variation in survivorship of larvae, prepupal and pupal period, and adult weight was noted by varying the prey species and prey abundance. Longer reproductive period (oviposition period) and shorter non-reproductive periods (preoviposition and postoviposition periods) were noted for females that fed on B. brassicae as compared to those that fed on A. pomi. Reproductive output was appreciably higher for females that fed on B. brassicae, and the fecundity decreased drastically under food shortage.