Establishing androgenesis, hybridization and clonal propagation in elite guava (Psidium guajava L.) cultivars

Guava (Psidium guajava L.) is member of Myrtaceae family. It is a significant fruit crop in Pakistan and rest of the world. It is being cultivated in tropical and subtropical climatic zones. Guava germplasm was explored by establishing androgenesis, its clonal propagation, selection and screening of good cultivars for crop improvement. In androgenesis, callus induction was achieved in medium size vegetative buds of winter crop store at 4 degree C for 48 hours. The androgenesis result showed that M2 medium accompanied with 0.3 mgL-1 2,4-D gave best response for callus induction in cv. Gola. The protocol was standardized for clonal propagation. We therefore, developed in vitro techniques to propagate guava through tissue culture. Various concentration of BAP were used to check the maximum shoot induction and plant regeneration. The result revealed that MS (Murashige and Skoog) medium supplemented with 3.0 mgL-1 BAP yielded maximum shoot induction percentage in both cvs. Gola and Surrahi, also check seasonal effect and best node position (1-3 node & 3-6 node). Two explant sources GHRP (Green House Raised Plants) & FGP (Field Grown Plants) were used. It was observed that explant from GHRP of summer crop with 36 node position gave best response in shoot induction in both the studied cultivars. The available germplasm in Fruit Garden, Square No.9, Institute of Horticultural Sciences, University of Agriculture, Faisalabad was explored by selection of healthy plants and then reciprocal crosses were made for hybrid fruit production on the basis of their physico-chemical analysis for germplasm preservation and crop improvement. Hybridization significantly enhanced the physical attributes of fruit viz fruit weight (114.05 g), fruit diameter (56.27 mm) and fruit length (67.99 mm). No. of seed per fruit (343.33), seed core weight (22.81 g) and total seed weight (3.03 g) of the fruit was also increased. While chemical attributes of fruit viz total soluble solids (10.53 %), titarble acidity (1.77 %), TSS: TA (19.61), ascorbic acid contents (285.33 mg/100ml), total sugar (7.92 %) and reducing sugar (4.38 %) were also increased after hybridization.