Fetal outcome in relation with Colour Doppler study of middle cerebral artery & umblical artery in intrauterine growth restriction

Background: The failure of the fetus to reach its genetically predetermined growth potential of sonographic estimated fetal weight (EFW) below 10th percentile for gestational age is called IUGR. This common clinical sign is fetal hypoxaemia. Therefore the challenge is to distinguish the constitutionally small but healthy fetus (Physiologically small) from pathologically small growth restricted fetus. Our objective is to study the fetal outcome in relation to Doppler study of middle cerebral artery and umbilical artery in intrauterine growth restriction (IUGR).Methods: The prospective study was conducted on 100 patients with suspected Intrauterine growth restriction. The subjects were evaluated by middle cerebral artery and umbilical artery velocimetries. Since no treatment is of any help to IUGR fetuses, the main stay of treatment still remains the timely delivery. Results: Mothers with abnormal velocimetries undergone more no of C-sections compared with mothers with normal velocimetries. Growth restricted fetuses with abnormal velocimetry in terms of APGAR score are more at risk of poor outcome. The average birth weight of neonates with abnormal Doppler study was lower when compared with neonates with normal velocimetry.Conclusion: With the Colour Doppler, the study of middle cerebral artery flow along with umbilical artery flows was useful in identifying IUGR and managing them in an appropriate way.

Evidence of Genomic Exchanges between Homeologous Chromosomes in a Cross of Peanut with Newly Synthetized Allotetraploid Hybrids

Cultivated peanut and synthetics are allotetraploids (2n = 4x = 40) with two homeologous sets of chromosomes. Meiosis in allotetraploid peanut is generally thought to show diploid-like behavior. However, a recent study pointed out the occurrence of recombination between homeologous chromosomes, especially when synthetic allotetraploids are used, challenging the view of disomic inheritance in peanut. In this study, we investigated the meiotic behavior of allotetraploid peanut using 380 SSR markers and 90 F2 progeny derived from the cross between Arachis hypogaea cv Fleur 11 (AABB) and ISATGR278-18 (AAKK), a synthetic allotetraploid that harbors a K-genome that was reported to pair with the cultivated B-genome during meiosis. Segregation analysis of SSR markers showed 42 codominant SSRs with unexpected null bands among some progeny. Chi-square tests for these loci deviate from the expected 1:2:1 Mendelian ratio under disomic inheritance. A linkage map of 357 codominant loci aligned on 20 linkage groups (LGs) with a total length of 1728 cM, averaging 5.1 cM between markers, was developed. Among the 10 homeologous sets of LGs, one set consisted of markers that all segregated in a polysomic-like pattern, six in a likely disomic pattern and the three remaining in a mixed pattern with disomic and polysomic loci clustered on the same LG. Moreover, we reported a substitution of homeologous chromosomes in some progeny. Our results suggest that the homeologous recombination events occurred between the A and K genomes in the newly synthesized allotetraploid and have been highlighted in the progeny. Homeologous exchanges are rarely observed in tetraploid peanut and have not yet been reported for AAKK and AABB genomes. The implications of these results on peanut breeding are discussed

Advances in genetics and molecular breeding of three legume crops of semi-arid tropics using next-generation sequencing and high-throughput genotyping technologies

Molecular markers are the most powerful genomic tools to increase the efficiency and precision of breeding practices for crop improvement. Progress in the development of genomic resources in the leading legume crops of the semi-arid tropics (SAT), namely, chickpea (Cicer arietinum), pigeonpea (Cajanus cajan) and groundnut (Arachis hypogaea), as compared to other crop species like cereals, has been very slow. With the advances in next-generation sequencing (NGS) and high-throughput (HTP) genotyping methods, there is a shift in development of genomic resources including molecular markers in these crops. For instance, 2,000 to 3,000 novel simple sequence repeats (SSR) markers have been developed each for chickpea, pigeonpea and groundnut. Based on Sanger, 454/FLX and Illumina transcript reads, transcriptome assemblies have been developed for chickpea (44,845 transcript assembly contigs, or TACs) and pigeonpea (21,434 TACs). Illumina sequencing of some parental genotypes of mapping populations has resulted in the development of 120 million reads for chickpea and 128.9 million reads for pigeonpea. Alignment of these Illumina reads with respective transcriptome assemblies have provided >10,000 SNPs each in chickpea and pigeonpea. A variety of SNP genotyping platforms including GoldenGate, VeraCode and Competitive Allele Specific PCR (KASPar) assays have been developed in chickpea and pigeonpea. By using above resources, the first-generation or comprehensive genetic maps have been developed in the three legume speciesmentioned above. Analysis of phenotyping data together with genotyping data has provided candidate markers for drought-tolerance-related root traits in chickpea, resistance to foliar diseases in groundnut and sterility mosaic disease (SMD) and fertility restoration in pigeonpea. Together with these traitassociated markers along with those already available, molecular breeding programmes have been initiated for enhancing drought tolerance, resistance to fusarium wilt and ascochyta blight in chickpea and resistance to foliar diseases in groundnut. These trait-associated robust markers along with other genomic resources including genetic maps and genomic resources will certainly accelerate crop improvement programmes in the SAT legum

Androgenesis in chickpea: Anther culture and expressed sequence tags derived annotation

181-188Double haploid technique is not routinely used in legume breeding programs, though recent publications report haploid plants via anther culture in chickpea (Cicer arietinum L.). The focus of this study was to develop an efficient and reproducible protocol for the production of double haploids with the application of multiple stress pre-treatments such as centrifugation and osmotic shock for genotypes of interest in chickpea for their direct use in breeding programs. Four genotypes, ICC 4958, WR315, ICCV 95423 and Arearti were tested for anther culture experiments. The yield was shown to be consistent with 3-5 nucleate microspores and 2-7 celled structures with no further growth. To gain a further insight into the molecular mechanism underlying the switch from microsporogenesis to androgenesis, bioinformatics tools were employed. The challenges on the roles of such genes were reviewed while an attempt was made to find putative candidates for androgenesis using Expressed Sequenced Tags (EST) and interolog based protein interaction analyses

Cytoplasmic male sterile systems in pigeonpea with special reference to A7 CMS

Compared to the cereals and vegetable crops, cytoplasmic male sterility is comparatively a new system available topigeonpea breeders to exploit heterosis/hybrid vigor. It has been possible to develop a CMS system for pigeonpea as crosspollination is possible in this crop. Various CMS systems have been developed for pigeonpea utilizing different wildrelatives from different gene pools. CMS based hybrids developed from A4 system have recorded superiority in yieldscompared to the checks on farmer’s fields. This has opened up a new window for yield improvement in pigeonpea. Thepaper discusses different CMS systems available for pigeonpea in general and the A7 system which was developed utilizingCajanus platycarpus, in particular

Unlocking the treasure chest for chickpea improvement: Utilisation of annual wild \u3cem\u3eCicer\u3c/em\u3e in wide crosses

Wild relatives among the genus Cicer have many valuable agronomic traits crucial for improvement of the cultivar. So far though, the treasure chest of natural diversity among wild Civer remains locked. Few Alleles have been successfully introgressed into chickpea (C. arietinum), and indeed few breeders even consider exploitation of Cicer species in their programs. One reason is that chickpea has no wild relatives within its own species, C. arietnum, and only two annual wild species are readily hybridised with chickpea using conventional crossing techniques. Therefore, a new approach is needed to utilise the more distantly related species in the secondary and tertiary genepools