European Journal of Biotechnology and Bioscience 26 European Journal of Biotechnology and Bioscience ISSN: 2321-9122 Impact Factor: RJIF 5.44 www.biosciencejournals.com Volume 6; Issue 2; March 2018; Page No. 26-30 Elucidation of the genetic basis of anther culture response and its breeding perspective in rice Swapan K Tripathy * , Digbijaya Swain, Dayanidhi Mishra, Arjun M Prusty, Suraj K Behera, P Tripathy, Bhaskar Chakma Department of Agricultural Biotechnology, College of Agriculture, OUAT, Bhubaneswar, Odisha, India Abstract Anther culture generates haploid plants which can be converted to pure breeding double haploids by colchicine treatment. In rice, anther culture is highly species and genotype specific. O. glaberrima L. responds more to callus induction and plantlet regeneration than Oryza sativa genotypes. In Oryza sativa L., japonica sub-group responds better than indica. Within indica sub- group, there is wide variation in anther culture response. Genetic basis for callus induction and green plantlet regeneration is still unclear. This limits the use of this technique for routine use in rice breeding. In this pursuit, the authors presented a detailed review of the genetic control of callusing and plant regeneration response for successful use of the anther culture technique in rice breeding. Keywords: anther culture response, genetic basis, double haploids, breeding perspectives, rice 1. Introduction Rice is the single most important cereal crop that feeds more than half of the world population and 70% Indians. Increasing productivity is continuing to be the top most priority to meet the food demand of expanding human population. With the alarming shrinking of natural resources (land and water) and adverse effects of climate change on agriculture, it becomes extremely difficult task to increase food production. At least 70% more food needs to be produced by 2050 to meet the food demand. Therefore, it compels rice breeders to reorient the breeding strategies and develop high yielding rice varieties. Conventional recombination breeding normally begins with hybridization between diverse parents followed by 6-9 cycles of selfing and 3-5 years of field evaluation before a pure breeding line being released as a new variety. In contrast, anther culture seems to be a suitable alternative technique that allows early fixation of homozygosity from even F 1 [39] . Genetic recombination occurs during micro-gametogenesis producing genetically unique male gametophyte. Anther culture induces haploid callus formation and a sizeable proportion (70%) of plantlets in culture are in vogue haploids which either do not survive till maturity or become sterile due to abnormal meiotic behaviour during gametogenesis. About 15-20% of haploid cells in the callus usually converted to immortal true breeding double haploid (DH) embryos due to spontaneous genome doubling. Besides, the recovery of DHs can be improved by colchicines treatment. Each DH line obtained in this way would bypass the inbreeding process [11] and produce a new true breeding line with unique gene combination. This allows creation of usable genetic variability and better discrimination between genotypes [34] resulting increased selection response. Thus, anther culture technique provides fertile double haploids (DHs) with fixed derived character combination that might otherwise disappear in the course of an extended series of segregating generations in conventional breeding methods. Varieties developed through anther culture can yield as high as 10.3t/ha under moderate fertility. The technique can be utilized for developing direct one-step homozygous transgenic plants [7] . Besides, the DH lines derived from anther culture of hybrids of genetically diverse parents are amenable for molecular mapping of valuable genes/QTLs. But, the technique poses several limitations. Early anther necrosis, recalcitrance to anther culture response, poor callus proliferation and more frequency of albino plants regeneration are the major problems in indica rice varieties [28] . At least 15,000 anthers need to be inoculated for in vitro culture to obtain regeneration of 150 plantlets [22] . Gueye and Ndir [13] could recover a total of 93 regenerants out of which 79 were albinos. The entire gamut of hinderance in anther culture response in rice and in particular indica rice is still unclear. Therefore, the authors reviewed the present status of rice research to unfold the genetic control of callusing and plantlet regeneration response in anther culture to help rice breeders in proper planning of double haploid breeding. 2. Anther/pollen culture in rice In vitro production of androgenic haploidy was first made possible in Datura by Guha and Maheswari [14] and in rice by Niizeki and Oono [37] . Since then several researchers attempted such novel technique to improve callus induction and for plantlet regeneration. Nirouli and Bimb [38] reported higher callus induction frequency in N6 medium with 2.5mg/l 2, 4-D (2, 4-dichloro-phenoxyacetic acid) + 0.5mg/l Kinetin (Kn) than N6 + 4mg/l NAA (Napthalene acetic acid) + 0.5mg/l Kn; but reverse was the case for green plant regeneration. Many researchers have reported genotypic specificity within indica subspecies by using improved media [52] . The F 1 hybrids are more responsive to anther culture than their parents. Xa and Lang [54] reported 5.13% to 9.27% callus induction and 6.17% to 14% regeneration from four crosses in