In Planta Androgenesis (Paternal Origin) in Saccharum X Erianthus Intergeneric Hybrid

The present investigation was carried in crosses made between Saccharum species hybrid clones i.e. Co 419, Co 7201 and Co 7224 (2n = 108-112) and Erianthus arundinaceus viz. IK 76-91 (2n = 60) and IK 76-99 (2n = 60) for introducing better ratoon ability, vigour, wide ecological adaptability, extensive root system, drought and water logging resistance, high biomass and disease resistance into modern sugarcane cultivars during 2020-23 at VSI-Sugarcane Breeding Centre, Amboli. Parental apomixis (paternal origin) has been recently noticed and it is unique in Saccharum X Erianthus intergeneric cross seedlings. A total of fifty-one seedlings were obtained from above three intergeneric crosses and out of these eighteen seedlings were reported as androgenetic seedlings as the female act as a surrogate mother. At the early stages, seed germination of seedlings was found two types i.e., one type resembling Saccharum and other resembling Erianthus with deep purple coloration. Morphologically androgenetic seedlings were similar to the male parents IK 76-91 and IK 76-99 with tall large tufted grass like clumps, vegetative stem with thick reproductive buds, root zone narrow and only one row of root eyes, the lamina gradually passes into leaf sheath with no auricle and dewlaps. Cytological studies were made in these seedlings and during metaphase the somatic chromosome number was observed to be 2n = 60 rather than expected 2n = 84-90. This paternal origin may be due to the ability of Erianthus male gametes to produce an embryo within the seed tissues of Saccharum species hybrids but without genetic contribution of the seed. Thus, in planta androgenesis is achieved through the combination of embryogenic behavior of male gametes which has entered in the ovule and the ability of ovules to act as a surrogate mother. They could derive either from the fusion of two male gametes or from the early natural diplodization of the haploid embryo. Such homozygous true breeding seedlings of Saccharum X Erianthus with hybrid vigour are extremely important in crop improvement. This system provides an unparalleled opportunity to shorten the breeding cycle and fix agronomic traits in the homozygous state. These androgenetic plants with Saccharum cytoplasm and Erianthus genome are male sterile making them highly useful for further hybridization and sugarcane improvement programme.