Sain Dass

Analyses of genetic diversity among maize inbred lines differing for resistance to pink borer and post-flowering stalk rot

Identification of the diverse sources of resistance is an important issue among the breeders for developing pest and disease free hybrids, to reduce the inoculum load, to prolong the life of inbred lines/hybrids and to reduce the cost of cultivation. Molecular diversity analysis was carried out among 23 maize inbred lines with respect to post flowering stalk rot and pink borer. Forty six SSR markers were employed among eight post flowering stalk rot (PFSR) and seven pink borer resistant lines along with eight other inbred lines to identify diverse resistant sources for developing resistant heterotic combinations to above pests and diseases. Number of alleles per SSR marker ranged from 2 to 9 averaging 4.11. The polymorphism information content (PIC) ranged from 0.272 to 0.839 with an average of 0.568. Discrimination rate (DR) of the markers ranged from 0.095 to 0.861 with a mean of 0.618. Number of alleles was highly correlated with PIC and DR. The pair-wise genetic dissimilarity values ranged from 0.05 to 0.84 with an overall mean of 0.64. Un-weighted neighbour joining clustering put 23 genotypes in two main clusters, which were further subdivided into 5 and 6 sub-clusters, respectively. We obtained 56 rare and 26 unique alleles in specific inbred lines, which can be used for identification of these lines. The present study has revealed considerable diversity among inbred lines differing for resistance against PFSR and pink borer; and provided ample scope for selection of parents for utilization in heterosis breeding

Differential effect of immature embryo's age and genotypes on embryogenic type II callus production and whole plant regeneration in tropical maize inbred lines (Zea mays L.)

The study was undertaken to elucidate the effect of genotypes and age of immature embryo on callus induction, embryogenic type II calli production and regeneration from immature maize embryos. The immature embryos were excised from a selfed ear of ten elite Indian maize inbred lines on 6, 12 and 18 days after pollination. The mean callus induction, embryogenic type II calli production, and regeneration was highest across all the genotypes in 12 days old immature embryos and were 44.25, 26.12, and 11.20 per cent respectively. The significant differences were observed with respect to callus induction, embryogenic type II calli production and regeneration capacity between genotypes. The highest regeneration capacity was observed by immature embryo at 12 days after pollination (DAP) of genotype HKI1105 and CM300.

Development of Database of Maize Hybrids and Open Pollinated Varieties Released and Notified for Cultivation in India

The maize database, first of its kind in India, is a central repository for cultivars i.e. hybrids and open pollinated varieties (OPVs) notified for cultivation in India since the inception of All India Coordinated Maize Improvement Project (AICMIP) in 1957. The database includes the information on cultivars developed from public as well as private breeding programmes. Besides, information on registered germplasm is also given. The database carries image gallery showcasing photographs of cobs/standing crop of the public-bred cultivars released after 1993.The database also presents information about adaptability of cultivars, average yield and disease, and insect-pest resistance along with the parental materials used in breeding programmes. Information on 31 descriptors as per Distinctivity, Uniformity and Stability (DUS) tests in respect of parental lines and their hybrids that were filed for protection under “Protection of Plant Varieties and Farmers Rights Act, 2001” (PPVFRAct, 2001) has been supplemented. In addition, the database provides contact information on developers of the notified cultivars thereby facilitating interactions among the members of maize community. The information contained within maize database can be accessed at on-line expert system called maize AGRIdaksh (www.iimr.res.in/maizeexpertsystem/www.agridaksh.iasri.res.in/maize). Information on notified cultivars (1961-2010) parental lines and cultivars (1993-2012) filed under PPVFRAct, 2001 can also be accessed at www.iimr.res.in/maizeexpertsystem/maize hybrids and composite varieties released in India. Whereas, information about registered germplasm (2003-2012) can be accessed at www.iimr.res.in/publications.

Specialty Corn for Nutritional Security and Dietary Diversification

Maize contributes more than half of the coarse cereal production in India. The grain is used for various purposes like feed, food, and several industrial purposes. It has tremendous potential to feed millions of hungry people of the African and Latin American countries as 5 % of world’s dietary energy supply comes from maize. In addition, maize has been considered as industrial crop as it is being used as a raw material in many important industries, viz., starch, oil, alcoholic beverages, food sweeteners, pharmaceuticals, cosmetics, textile, paper, film, tire, food processing, packing, biofuel, etc. for developing hundreds of industrial products. Apart from these, quality protein maize (QPM) is being grown to meet the nutritional requirement of underprivileged. Besides these uses, sweet corn (SC) and baby corn (BC) are used for ensuring livelihood and green fodder security in peri-urban areas while popcorn (PC) is used as a nutritional alternative snack, etc.