Polygenic variations and character association of morphological, biochemical and disease related traits in garlic (Allium sativum L.)

A field investigation was carried out at Bihar Agricultural University Sabour, Bhagalpur, Bihar, India during Rabi season 2016-17. The study comprised 38 garlic genotypes. These were evaluated to assess the mean performance and to find out inter relationship between field performance of genotype and storage loss of garlic. Results revealed that the mean squares due to genotypes were highly significant for all the traits. The maximum plant height (49.04 cm) was recorded in genotype BRG-13 and lowest was recorded (34.49 cm) in RG-463. The maximum number of leaves per plant was observed in WG-73 (9.22) and minimum in BRG-3 (6.57). The bulb yield per plant was maximum in line BRG-13(34.65 g) and minimum in G-1 (20.63g). Disease severity (%) was found least in the genotype IC-290440 (4.26%) and maximum (40.36%) in genotypes 507 (40.36%).The least percent disease index of stemphylium blight was recorded in genotype BRG-13(10.55%) while the highest percent disease index of stemphylium blight was found in BRG-3 (48.71%). least Botrytis porri infestation percentage was obtained in genotype WG-7(4.25%). However, the highest percentage was recorded in genotype RG-464 (22.19%). least black mould infestation percentage was recorded in 650 (2.56%). However, the maximum infestation percentage (9.25%) was obtained in genotype WG-48. Genotype BRG-13 exhibited maximum total phenol content (1.86 µg gallic acid/g) in leaves. However, the lowest amount of was noticed in BRG-3 (0.30 µg gallic acid/g) genotype. Maximum total phenol content in cloves was recorded in genotype BRG-13 (0.65 µg gallic acid/g) and the lowest amount of was observed in BRG-3(0.11 µg gallic acid/g).Maximum total soluble solid content was found in genotype 650 (39.37o Brix) followed by 4 (37.93o Brix) followed by IC-290440 (37.91oBrix), whereas, minimum amount of total soluble solid was observed in WG-39 (26.49oBrix). Wide variability was present among morphological, biochemical and disease parameters under study suggesting ample scope of selection. The higher magnitude of phenotypic coefficient of variations (PCV) than genotypic coefficient of variations (GCV) for all the traits indicated environmental factor influencing their expression and high magnitude of PCV and GCV for all the characters under study pointed toward ample scope for improvement of these traits through selection. Genotypic coefficient of variation (GCV) and phenotypic coefficient of variation (PCV) was high in total soluble solid. High heritability was observed for total phenol content in leaves(98.31), total phenol content in cloves (99.64), total soluble solid (84.04), PDI % (84.59), D S % (97.77), Botrytis porri % (99.00), Black mould % (99.22), yield per plant (83.26), suggesting that selection for these traits would be effective.