An investigation was done to study the heterotic grouping and patterning in quality protein maize inbreds. Biochemical screening resulted in the choice of 3 inbreds each with high (UQPM 2, UQPM 4, and UQPM 21) and low (UQPM 18, UQPM 19, and UQPM 20) lysine and tryptophan contents respectively for genetic studies using diallel analysis. UQPM 20 × UQPM 18 was notable as it possessed high standard heterosis and specific combining (sca) effect for grain yield, protein, tryptophan, and lysine. Based on yield sca, the 6 parental inbreds were classified into 3 heterotic groups. Intergroup cross UQPM 20 × UQPM 18 was the best in yield and quality. The superior heterotic pattern was flint × dent. In genetic diversity analysis using simple sequence repeat markers, the inbreds of the best hybrid, UQPM 20 × UQPM 18, lay in same cluster but different subclusters. Correlations between genetic distance and sca effects were low for grain yield, which hampers the prediction of heterosis from molecular data alone.

Pearl millet is a staple food crop for millions of people living in the arid and semi-arid tropics. Molecular markers have been used to identify genomic regions linked to traits of interest by conventional QTL mapping and association analysis. Phenotypic recurrent selection is known to increase frequencies of favorable alleles and decrease those unfavorable for the traits under selection. This study was undertaken (i) to quantify the response to recurrent selection for phenotypic traits during breeding of the pearl millet open-pollinated cultivar “CO (Cu) 9” and its four immediate progenitor populations and (ii) to assess the ability of simple sequence repeat (SSR) marker alleles to identify genomic regions linked to grain and stover yield-related traits in these populations by association analysis. A total of 159 SSR alleles were detected across 34 selected single-copy SSR loci. SSR marker data revealed presence of subpopulations. Association analysis identified genomic regions associated with flowering time located on linkage group (LG) 6 and plant height on LG4, LG6, and LG7. Marker alleles on LG6 were associated with stover yield, and those on LG7 were associated with grain yield. Findings of this study would give an opportunity to develop marker-assisted recurrent selection (MARS) or marker-assisted population improvement (MAPI) strategies to increase the rate of gain for pearl millet populations undergoing recurrent selection.

Twenty pigeonpea specific SSR markers were used to test the molecular diversity among 21 cultivated genotypes and three wild species. Twelve markers were monomorphic and twenty two alleles were produced by eight polymorphic markers. Ten markers were transferrable among the cultivated and wild species. The PIC value of the markers ranged from 0.081(PGM 3 and PGM 82) to 0.603 (PGM 106). The average PIC value of the markers was 0.30. Based on the dendrogram constructed using the dissimilarity values, 24 accessions were grouped into two main clusters. Main cluster I comprises all the cultivated genotypes, and wild species <italic>viz., Cajanus scarabaeoides</italic> and <italic>Cajanus cajaniolius. Cajanus sericeus</italic> formed the separate cluster (Main cluster II). Within the main cluster I, seven sub-clusters were observed. <italic>Cajanus scarabaeoides</italic> and <italic>Cajanus cajaniolius</italic> formed a separate sub-cluster within the main cluster I. Most of the diversity was observed in between the wild species and cultivated genotypes. There is no significant molecular diversity among the cultivated genotypes. Such a narrow genetic base is likely to represent a serious impediment to breeding programs in pigeonpea. This study suggested the need for broadening the genetic base of cultivated genotypes to improve the productivity of the crop.

No abstract

The present study was initiated with forty microsatellite markers for studying the molecular genetic diversity in 28 pigeonpea genotypes (6 CGMS lines of A₁, A₂ and A₄ sources, their maintainer lines and 16 inbred lines) utilised as the parental material for the synthesis of F₁ hybrids. The level of polymorphism was too low and only 45 per cent markers were polymorphic. A total of 65 alleles were produced and the number of alleles produced ranged from two to six. The mean PIC value of 40 SSR primers was 0.147 and the primer CcM2977 produced the highest PIC value of 0.787 followed by CcM1770 (0.565). The primers <italic>viz.</italic>, CcM0039 and CcM2463 were polymorphic between CGMS and inbred lines and the primer CcM2977 was polymorphic among the different sources of CGMS lines. The UPGMA clustering and Neighbour-joining analyses grouped all the CGMS lines and respective maintainer lines in a single cluster and the inbred lines as two separate clusters. Among the inbred lines ICPL 11966, ICPL11947 and ICPL11950 were distinctly grouped in one cluster and other 13 inbred lines were clustered separately. Polymorphic markers <italic>viz.</italic>,CcM2977 and CcM1770 were used to confirm the hybrids of the crosses <italic>viz.</italic>, ICPA 2043 x LRG 41 and ICPA 2043 x IC 33725. The present study revealed that SSR markers are highly informative for exploiting the molecular diversity prevailing among the parental lines and could be utilized for further pigeonpea improvement at genomic level.

No abstract

A high yielding Prosomillet culture, TNAU 151, was developed at the Department of Millets, Centre for Plant Breeding and Genetics, Tamil Nadu Agricultural University, Coimbatore and tested at national level for three years from 2005 to 2008. It is a non-lodging, fertilizer responsive and early maturing culture selected from the segregants of the cross involving TNAU 96 X PV 1673. Its average yield is 1860 kg of grain and 4130 kg of straw per hectare under normal condition. It is a medium tall, profusely tillering, non shattering and non-lodging variety and is highly suitable for dry lands of India. The panicle is large and branched. The grains are bold and golden yellow in colour. Being a short duration culture (72 days), it is the best suited crop for contingency planting. Under All India Coordinated Trials, this culture has registered an average yield of 1860 kg/ha which was 10.36 and 14.44 percent increase over TNAU 149 and DHPM 50-1-1 (qualifying checks) and 35.35 and 35.45 percent increase over national checks GPUP 21 and K 1 respectively. Based on the consistent superiority in yield performance, the prosomillet advanced culture TNAU 151 was released as a national variety in the year 2008.

The cowpea culture COCP 702, a 20 kR gamma ray mutant derivative of CO 4 tested in station and district trials and as Co Vu 702 in the All India Coordinated trials of Arid legumes was released as a new cowpea variety CO(CP) 7 for general. cultivation in Tamil Nadu. The culture COCP 702 recorded an average yield of 900 kg/ha registering 18.9, 19.3 and 14.3 per cent increased yield over CO 6, P 152 (C 152) and Vamban 1 varieties respectively, when it was tested in 144 trials including 104 trials under farmers holdings (ART). It is suitable for cultivation in all the three seasons, where cowpea is grown in Tamil Nadu and it matures in 65-70 days. The resistance levels of this culture against major pests and diseases are on par with CO 6. The grain colour, appearance, flavour, texture and taste of COCP 702 is more preferred by the consumers compared to CO 6.