Vinay Mahajan

Biodiversity in the barnyard millet (Echinochloa frumentacea Link, Poaceae) germplasm in India

One hundred ninety four accessions of barnyard millet collected from different eco-geographical regions of India were evaluated for 14 quantitative traits during kharif 2003 and 2005. These accessions were grouped into 5 groups on the basis of place of collection. These groups differed significantly in their mean values for quantitative traits and magnitude of correlation among traits indicates origin based association. The group ‘C’ (source of origin is unknown) was found most diverse group (mean coefficient of variation 17.67%), while rest of the groups recorded mean coefficient of variation between 12 and 13%. Correlation studies indicate that flag leaf width, number of racemes along with internode length should be considered while performing selection in segregating generations. The plotting of first and second principal component axes scores suggests that presence of three distinct morphotypes in the present study. These morphotypes are quite similar to three botanical varieties viz., var. robusta, var. intermedia and var. stolonifera in their morphological traits, while botanical variety laxa (endemic to Sikkim area of India) was completely absent from the present study.

Textural, nutritional and functional attributes in tomato genotypes for breeding better quality varieties.

BACKGROUND Screening of natural biodiversity for their better quality attributes is of prime importance for quality breeding programmes. A set of 53 tomato genotypes was measured for their textural [skin firmness, pericarp thickness, total soluble solids (TSS)], nutritional [phosphorus (P), potassium (K), iron (Fe), zinc (Zn), copper (Cu), manganese (Mn) and titrable acidity (TA)] and functional (beta-carotene, lycopene and ascorbic acid) quality attributes. RESULT Three sets of data (textural, nutritional and functional attributes) were obtained and analysed for their mutual relationships. Wide variations were observed in most of the measurements, e.g. skin firmness (coefficient of variability (CV) 269-612 g), pericarp thickness (CV 1.4-4.9 mm), potassium (CV 229-371 mg 100 g(-1)), iron (CV 611-1772 mg 100 g(-1)), ascorbic acid (CV 12-86 mg 100 g(-1)), suggesting that there are considerable levels of genetic diversity. Significant correlations (P < 0.05, 0.01) were also detected among different attributes of tomato genotypes, such as phosphorus and zinc with a correlation coefficient of 0.74, ascorbic acid and copper of 0.57, pericarp thickness and lycopene of - 0.52. However, there were no correlations between textural and nutritional attributes. Five factors were computed by principal component analysis that explained 66% of the variation in the attributes, among which all micronutrients other than iron, TSS, firmness and beta-carotene were most important. Functional attributes except beta-carotene played a less important role in explaining total variation. CONCLUSION This knowledge could aid in the efficient conservation of important parts of the agricultural biodiversity of India. These results are also potentially useful for tomato breeders working on the development of new varieties.

Screening barnyard millet germplasm against grain smut ( Ustilago panici-frumentacei Brefeld)

Barnyard millet accessions (257) were inoculated with grain smut spores at anthesis stage during 2003. Seed produced on inoculated ear heads was sown in 2005 and resulting plants evaluated for ten morphological traits and grain smut incidence. The accessions were grouped into seven groups based on origin. The lowest mean grain smut incidence was recorded for advance breeding lines, while highest mean value was observed for Uttarakhand group. Genes determining grain yield and susceptibility to grain smut were at most loosely linked as evidenced by non-significant correlations between grain smut incidence and grain yield in six out of seven groups as well as whole collection. Smut resistance along with grain yield in barnyard millet can be enhanced by adopting proper breeding strategy; therefore, in segregating generations, selection should be carried out for both characters simultaneously.

‘Vivek Matar 11’: A New Garden Pea Cultivar

Garden pea (Pisum sativum L. var. hortense) is cultivated during winter in subtropical and early spring in temperate zones. The major constraint to its cultivation, especially in low- and mid-hills, is infection by the causal organism of powdery mildew. Varietal diversification is needed to develop early- and medium-duration resistance to powdery mildew. Breeding work was initiated to develop a high-yielding garden pea cultivar with medium maturity, dark green pods, and resistance to powdery mildew. ‘Vivek Matar 11’ is a new garden pea cultivar developed by hybridization between ‘Azad Pea 1’ × ‘PRS-18-6-4-5-1’. It is a medium maturity cultivar having attractive long green curved pods with 8–10 sweet seed/pod and is highly resistant to powdery mildew. Average green pod yield is 10–11 Mt·ha−1. It is suitable for cultivation under organic and inorganic conditions. This cultivar may be adapted to other temperate regions of the world.

Rainfall trends and maize productivity in diverse agro-climatic regions of India

Historical data on climatic parameters as well as yield data on maize are important to look into past setbacks and achievements. In the present study, we have analysed the grain yield of the best entry, the best check and trial mean of full season maturity group grown during the monsoon (kharif) season in All India Coordinated Maize Improvement Project (AICMIP) trials from 1991 to 2012 in four agro-climatic zones of the country. The monthly fluctuations in rainfall during maize cropping season are high in all the zones during maize crop season and the trend was significantly increasing in the month of August in Zone V. The seasonal rainfall decreased during the month of October in all the Zones. The yield performance of best test entry was at par or higher than the best check with significant and strong correlation with each other and with trial mean. There was increasing trend for maize yields from 1991 to 2012 in all the zones. The new maize hybrids from AICMIP are superior even under the changing climatic conditions in different agro-climatic zones, however, there was a stabilization of the zonal yields (pooled over states within agro-climatic zones) of maize around year 2002 for 7 to 12 years in different zones of the country. In spite of high fluctuations in rainfall, there was continuous improvement in the new genotypes developed at AICMIP especially in past two decades. Thus, AICMIP had an important contribution in overall increase in zonal yields of the country even though the differential impact in different zones. The impact of new hybrids in zonal or state productivity and production took less time for Zone II and Zone III and this impact lasted for more years in Zone II than Zone III.

Altitudinal diversity in horsegram (Macrotyloma uniflorum (Lam.) Verdc.) landraces collected from Himalayan hill region.

A total of 54 horsegram landraces collected from three altitudinal zones (lower hills, mid hills and higher hills) of Himalayan region were characterized and evaluated for nine quantitative characters. Accessions collected from lower and higher hills were more diverse and differed significantly from mid hills accessions for characters viz., days to flowering, days to physiological maturity, plant height and grain yield per plant. The plotting of first and second principal component axes scores revealed that there was dispersion among the accessions collected from different altitudinal groups. It reveals a less variability among the landraces collected from same altitudinal group but high variability among the landraces collected from different altitudes. This suggests that the horsegram landraces are adapted to specific zone due to different selection pressure practiced by the farmers at different altitudes. Farmers in lower and higher hills select the landraces having high grain yield coupled with less reproductive phase duration and taller in nature.