Amongst the fibres, Cotton is under cultivation from ancient period as a source of a fibre in India. Development of superior varieties and exploitation of phenomenon of heterosis are the main breeding approaches followed for developing high yielding varieties in respect to cotton. The field trials with fifty five genotypes (10 parents and 45 crosses) along with local released hybrid as a check PKV Hy–2 in two sets of environmental conditions were conducted using Completely Randomized Block Design (CRBD) on farm of University Department of Agricultural Botany, Dr PDKV, Akola (MS) as per procedure for Diallel analysis given by Griffings, 1956. The heterosis is the genetic expression of the beneficial effects of hybridization and specifically in cotton, the hybrid vigour is a target for all most all cotton breeders. The data were recorded for all the fourteen morphological including fibre quality characters viz., days to 50 per cent flowering, plant height (cm), number of monopodia per plant, number of sympodia per plant, number of bolls per plant, boll weight (g), number of seeds per boll, ginning outturn (%), seed index (g), lint index (%), 2.5 per cent span length (mm), fibre strength (g/tex), micronaire value (?g/inch) and seed cotton yield per plant (g). The maximum estimates of heterosis and heterobeltiosis for seed cotton yield per plant was observed in JLH–1594 x AKH–24 (74.21 and 58.67 per cent) followed by KH–118 x AKH–62 (73.06 and 54.03 per cent) over environments, whereas KH–118 x AKH–62 surpassed among all the forty five crosses for useful heterosis (22.84 per cent) over the locally adapted upland cotton hybrid PKV Hy–2