Morphological characterization of intra-varietal heterogeneity in 'Dashehari' mango ( Mangifera indica L.)

Mango, propagated commercially through vegetative means, ensures multiplication of true to type plants. Despite this, intra-varietal variability is reported in certain varieties although limited. In the present study, 45 'Dashehari' trees, 25-30 years in age from 15 different orchards in 2 blocks viz. Malihabad and Mall from Agri-Export Zone for mango from Uttar Pradesh, India were selected for studying intravarietal variability through morphological characterization which was further elucidated by variation in stomatal characteristics through Scanning Electron Microscopy. The significant variability in trunk girth was observed to range from 102.50 to 151.33, number of secondary branches per plant 12 to 29, leaf length 17.45 to 22.55 cm, leaf width 3.95 to 5.62 cm, leaf thickness 0.21 to 0.38 mm and petiole length 2.42 to 4.35 cm. Among fruit characters fruit weight ranged from 191.00 to 342.33 g, fruit volume 175.83 to 325.00 mL, specific gravity of fruit 1.02 to 1.10 g mL(-1), fruit width 5.52 to 6.97 cm, fruit length 9.83 to 12.85 cm, pulp weight 125.83 to 259.67 g, peel weight 40.00 to 61.67 g, pulp: peel ratio 2.72 to 4.38 and peel thickness 1.24 to 2.78 mm. Stone weight was found to vary ranging from 24.17 to 32.33 g, pulp: stone ratio 4.37 to 8.03, volume of stone 22.67 to 31.83 mL, specific gravity of stone 1.01 to 1.10 g mL(-1), length of stone 8.98 to 11.75 cm, width of stone 2.70 to 4.13 cm and thickness of stone 1.52 to 1.92 cm. The seed kernel length was observed to range from 3.65 to 6.63 cm, width of kernel 1.45 to 4.13 cm and thickness of kernel 1.04 to 2.07 cm. A corresponding variability was recorded for stomata length 6.00 to 17.56, stomata width 5.12 to 15.00, stomatal size viz. pore width ranging from 1.68 to 6.56 mu m and pore length ranging from 2.32 to 11.70 mu m and stomatal density ranging from 24 to 46 mm(-2) and. Statistical analysis revealed significant intra-varietal heterogeneity observed in 'Dashehari' accessions which were grouped into two groups on the basis of cluster analysis.