Strict Positive Realness of Descriptor Systems in State Space

In this paper we give necessary and sufficient spectral conditions for various notions of strict positive realness for single input single output, impulse free Descriptor Systems. These conditions only require calculation of eigenvalues of a single matrix. A characterization of a KYP-like lemma for descriptor systems is also derived, and its implications for the stability of a class of switched descriptor systems are briefly discussed

Clinico-Surgical Outcome of Repair of Isolated Atrial Septal Defect At Care Hospital, Banjara Hills-Hyderabad India, 2004-2006

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Impact of Genomics on Chickpea Breeding

Chickpea is an economical source of vegetable protein for the poor living in the semi-arid regions globally. As a consequence of climate change and increasing climate variability, the incidences of drought and heat stresses and severity of some diseases, such as dry root rot and collar rot, have increased in chickpea crop, resulting in poor and unstable yields. By improving the efficiency of crop breeding programs, climate resilient varieties with traits desired by the farmers, industries and consumers can be developed more rapidly. Excellent progress has been made in the development of genomic resources for chickpea in the recent past. Several national and international chickpea breeding programs have started utilizing these genomic resources and tools for genetic improvement of complex traits. One of such examples includes the introgression of “QTL-hotspot” containing quantitative trait loci (QTLs) for several drought tolerance-related traits, including root traits, through marker-assisted backcrossing (MABC) for enhancing drought tolerance in popular cultivars. Several drought-tolerant introgression lines with higher yield as compared to the popular cultivars have been identified. Multi-parent advanced generation intercross (MAGIC) populations developed from using 8 parents created large genetic diversity consequently several promising lines. Marker-assisted recurrent selection (MARS) has also been explored for yield improvement in chickpea. Development of diagnostic markers or the identification of candidate genes for several traits is essential for greater use of genomic resources in chickpea improvement

Inheritance of protein content and its relationships with seed size, grain yield and other traits in chickpea

Chickpea (Cicer arietinum L.), the second largest grown pulse crop of the world, is an important source of protein for millions of people, particularly in South Asia. Development of chickpea cultivars with further enhanced levels of protein is highly desired. This study was aimed at understanding the genetic control of protein content and its association with other traits so that suitable breeding strategies can be prepared for development of high protein content cultivars. A high protein (29.2 %) desi chickpea line ICC 5912 with pea-shaped small seed, grey seed coat and blue flower was crossed with a low protein (20.5 %) kabuli line ICC 17109 with owl’s head shaped large seed, beige seed coat, and white flower. The F2 population was evaluated under field conditions and observations were recorded on protein content and other traits on individual plants. The protein content of F2 segregants showed continuous distribution suggesting that it is a quantitative trait controlled by multiple genes. The blue flowered segregants had pea shaped seed with grey seed coat, while the white flowered segregants had owl’s head shaped seed with beige seed coat indicating pleiotropic effects of gene(s) on these traits. On an average, blue flowered segregants had smaller seed, lower grain yield per plant and higher protein content than the pink flowered and the white flowered segregants. The protein content was negatively correlated with seed size (r = −0.40) and grain yield per plant (r = −0.18). Thus, an increment in protein content is expected to have a negative effect on seed size and grain yield. However, careful selection of transgressive segregants with high protein content along with moderate seed size and utilizing diverse sources of high protein content will be usefull in developing chickpea cultivars with high protein content and high grain yield

Effect of post-emergence herbicide imazethapyr on phenological and agronomic traits in chickpea breeding lines

Chickpea is sensitive to herbicides and manual weeding is currently the only option for weed control in many developing countries in arid and semi-arid regions of the world. The farmers in these countries need herbicide-tolerant varieties to use post-emergence herbicides to control weeds. In this direction, a study was conducted with 21 breeding lines at four locations in India (Patancheru, Bijapur, Nandyal and Sehore) during postrainy season of 2014-15. The trial was conducted under field conditions in RBD with four replications in both control (hand weeding) and sprayed (herbicide: Imazethapyr @ 750 ml/ha) treatments. The herbicide was sprayed 30 days after sowing. Herbicide effect was studied on phenological (days to flowering and maturity) and agronomic (number of primary and secondary branches, plant height, seed yield, 100-seed weight and harvest index) traits. The results indicated that time to flowering and maturity was delayed up to 16.5 and 18.5 days, respectively. Herbicide had no effect on primary branches, while the number of secondary branches was increased up to 12. Plant height was severely reduced by 18cm. The reduction in seed yield was observed up to 49%, whereas 100-seed weight was increased across locations. Location-specific superior lines (Nandyal: ICCIL 04016, ICCIL 04004, ICCV 10114; Patancheru: ICCIL 04007; Bijapur: ICCV 04516, ICCV 10, ICCV 97105, ICCIL 01026, ICCV 09106; Sehore: ICCV 08102) were identified. These lines can be used as potential sources for developing herbicide tolerant varieties in chickpea. Weed management through herbicides is economical and facilitates minimum tillage methods, which help preserve topsoil

High yielding and drought tolerant genotypes developed through marker-assisted back crossing (MBAC) in chickpea

Chickpea (Cicer arietinum L.) is the second largest grown food legume crop in the world after common bean. This crop is largely grown under rainfed conditions in Asia and sub-Saharan Africa where terminal drought is the major production constraint. Generation of large scale genomic resources in chickpea during the recent years has made it possible to improve the complex traits like drought tolerance. A “QTL-hotspot” harbouring QTLs for several root and drought tolerance traits was transferred from the drought tolerant line ICC 4958 to a leading chickpea cultivar JG 11 (ICCV 93954), and a widely adapted cultivar Bharati (ICCV 10) in India. A set of 20 BC3F4/ BC3F5 introgression lines (ILs) of JG 11 and 22 of Bharati were evaluated at three to four locations (Patancheru, Nandyal, Gulbarga and Dharwad) in Southern India over two years during 2011-12 to 2014-15. Many lines giving at least 10% higher yield than the recurrent parents JG 11 and Bharati were identified at each location and in each growing condition (rainfed/irrigated). As the introgressed genomic region also influences seed size, most ILs had bigger seed than the recurrent parents. These results are very encouraging and demonstrate the effectiveness of marker-assisted breeding in improving terminal drought stress tolerance in chickpea

MAGIC lines in chickpea: development and exploitation of genetic diversity

In chickpea a multi-parent advanced generation intercross (MAGIC) population was developed using eight parents that are improved varieties and widely adaptable breeding lines. The main objective was to enhance the genetic diversity and bring novel alleles for developing superior chickpea varieties. The development scheme involved a sequence of 28 two-way, 14 four-way and 7 eight-way crosses, followed by bulking of final F1 plants. From F2 generation onwards single plants were grown as progenies and advanced to F8 by single seed descent method. The finally developed 1136 MAGIC lines were phenotyped under rainfed (RF) and irrigated (IR) conditions for 2 years (2013 and 2014) under normal season, and one year under heat stress (HS) condition (summer-2014) in field to estimate the genetic diversity created among these lines. Under RF-2014, RF-2013, IR-2014, IR-2013 and S-2014 seasons 46, 62, 83, 50 and 61 lines showed significantly higher grain yield than the best parent, respectively. Similarly, 23 and 19 common lines were identified under RF and IR conditions over two years and no common line was identified between RF/IR and HS conditions. Preliminary evaluation showed a large variation among MAGIC lines for flowering time (34–69 days), maturity (80–120 days), plant height (23.3–65 cm), grain yield (179–4554 kg/ha), harvest index (0.10–0.77) and 100 seed weight (10–45 g) under RF and IR conditions. Several genotypes with higher grain yield than the best check under heat stress were identified. These MAGIC lines provide a useful germplasm source with diverse allelic combinations to global chickpea community

Finger Millet Improvement in Post-genomic Era: Hundred Years of Breeding and Moving Forward

Finger millet, grown on about 5 Mha globally under semi-arid environments of East Africa and South Asia, serves as an important dual-purpose crop to address food, forage, and nutritional needs in these marginal regions. Despite the tremendous yield potential, the area cultivated for small millets, including finger millet, decreased by 25.7% globally between 1961 and 2018. Finger millet improvement program began in 1913 in India; however, concentrated efforts to realize genetic gains in this climate-resilient crop are yet to be deployed compared to the efforts invested in improving other major cereals. This has resulted in lower productivity of finger millet in farmer’s fields than its potential yield even after more than 100 years of breeding. However, significant genetic variability is available for traits of importance. The breeding programs in Asia and Africa have refined the hybridization techniques and breeding objectives as per local needs. ICRISAT, an international center with finger millet as one of its mandate crops, is engaged with partners to generate new germplasm to enhance the productivity of this crop in marginal regions. This program, based in India and Kenya, has developed and distributed germplasm and breeding lines globally in the last few decades. Many promising and widely adapted cultivars have been released and adopted in many countries. Hybridization between the Indian and African gene pools of finger millet in the 1990s brought a paradigm shift in finger millet production in India. Now, breeding pipelines have been strengthened with the identification of newly identified germplasm for traits of importance, especially for blast resistance. Recently, finger millet genome sequencing was accomplished, and with the availability of advanced phenotyping protocols for various traits of importance, it has opened new opportunities to enhance genetic gains in this crop. This chapter informs about historical breeding efforts and discusses the prospects and challenges of finger millet breeding to enhance breeding efficiency and genetic gains in finger millet. International collaborative efforts toward improving agronomic traits, value addition, and the trade value of finger millet would help marginal farmers of southeast Asia and Africa but will also help enhance the commercial value of this underutilized millet

Capturing genetic variability and selection of traits for heat tolerance in a chickpea recombinant inbred line (RIL) population under field conditions

Chickpea is the most important pulse crop globally after dry beans. Climate change and increased cropping intensity are forcing chickpea cultivation to relatively higher temperature environments. To assess the genetic variability and identify heat responsive traits, a set of 296 F8–9 recombinant inbred lines (RILs) of the cross ICC 4567 (heat sensitive) × ICC 15614 (heat tolerant) was evaluated under field conditions at ICRISAT, Patancheru, India. The experiment was conducted in an alpha lattice design with three replications during the summer seasons of 2013 and 2014 (heat stress environments, average temperature 35 °C and above), and post-rainy season of 2013 (non-stress environment, max. temperature below 30 °C). A two-fold variation for number of filled pods (FPod), total number of seeds (TS), harvest index (HI), percent pod setting (%PodSet) and grain yield (GY) was observed in the RILs under stress environments compared to non-stress environment. A yield penalty ranging from 22.26% (summer 2013) to 33.30% (summer 2014) was recorded in stress environments. Seed mass measured as 100-seed weight (HSW) was the least affected (6 and 7% reduction) trait, while %PodSet was the most affected (45.86 and 44.31% reduction) trait by high temperatures. Mixed model analysis of variance revealed a high genotypic coefficient of variation (GCV) (23.29–30.22%), phenotypic coefficient of variation (PCV) (25.69–32.44%) along with high heritability (80.89–86.89%) for FPod, TS, %PodSet and GY across the heat stress environments. Correlation studies (r = 0.61–0.97) and principal component analysis (PCA) revealed a strong positive association among the traits GY, FPod, VS and %PodSet under stress environments. Path analysis results showed that TS was the major direct and FPod was the major indirect contributors to GY under heat stress environments. Therefore, the traits that are good indicators of high grain yield under heat stress can be used in indirect selection for developing heat tolerant chickpea cultivars. Moreover, the presence of large genetic variation for heat tolerance in the population may provide an opportunity to use the RILs in future-heat tolerance breeding programme in chickpea

Molecular mapping of dry root rot resistance genes in chickpea (Cicer arietinum L.)

Dry root rot (DRR) caused by Rhizoctonia bataticola [(Taub.) Butler] is an emerging disease of chickpea (Cicer arietinum L.) and a serious constraint to chickpea production in warm and arid regions. To identify the genomic regions conferring resistance to DRR, a total of 182 F9 derived Recombinant Inbred Lines (RILs) were developed from the cross between a susceptible line BG 212 and moderately resistant breeding line ICCV 08305. The parental lines and RILs were screened against Rb 6 isolate of R. bataticola using paper towel method under controlled environment at ICRISAT during 2016 and 2017. The RILs were genotyped with cost-effective SNP genotyping platform, Affymetrix Axiom CicerSNP array. As a result, a high-density genetic map with 13,110 SNP markers spanning 1224.11 cM with an average inter marker distance of 0.09 cM was developed. A single minor QTL (‘qDRR-8’) explaining 6.70% PVE with LOD scores 3.34 was identified on CaLG08 for DRR resistance which could be further explored for mining candidate genes and the linked SNP markers could be further validated for application in marker-assisted selection of DRR resistance in chickpea breeding programs