KUMAR AND ABBO tIme are descfJbed WIth speClal reference to theIr effect on chIckpea adaptation, seed weIght, seed YIeld, and stabIlity under semIafJd Near-East and IndIan subcontInen tal growmg enVIronments. It IS suggested that the genetic research on fl owermg orne of thlS speCles and its wild relanves needs much attentIon, as only two genes affectIng t1us traIt are IdentIfied so far. Genes allowmg a reduced crop cycle WIll provide pathways for new crOpplOg systems and mcreased populatton denSIty. Re duced crop duratIon may also help chIckpea escape damage by the major blOttc and ablOtIC stresses that mostly affect the crop at fl owermg and poddmg stages. It IS concluded that the relatIvely SImple mhentance of flowermg tIme opens up new pOSSIbIlItIes for breedmg hIgh YIeldmg and stable cluckpea cultIvars for the setnlarld and arId reglOlls globally

Rising temperatures and drought stress limit the growth and production potential of lentil (Lens culinaris Medikus), particularly during reproductive growth and seed filling. The present study aimed to (i) investigate the individual and combined effects of heat and drought stress during seed filling, (ii) determine the response of lentil genotypes with contrasting heat and drought sensitivity, and (iii) assess any cross tolerance in contrasting genotypes. For this purpose, eight lentil genotypes (two drought-tolerant, two drought-sensitive, two heat-tolerant, two heat-sensitive) were either sown at the normal time (second week of November 2014), when the temperatures at the time of seed filling were below 30/20°C (day/night), or sown late (second week of February 2015) to impose heat stress (temperatures > 30/20°C (day/night) during reproducive growth and seed filling. Half of the pots in each sowing environment were fully watered throughout (100% field capacity) while the others had water withheld (50% of field capacity) from the start of seed filling to maturity. Both heat and drought, individually or in combination, damaged cell membranes, photosynthetic traits and water relations; the effects were more severe with the combined stress. RuBisCo and stomatal conductance increased with heat stress but decreased with drought and the combined stress. Leaf and seed sucrose decreased with each stress in conjunction with its biosynthetic enzyme, while its (sucrose) hydrolysis increased under heat and drought stress, but was inhibited due to combination of stresses. Starch increased under heat stress in leaves but decreased in seeds, but drastically declined in seeds under drought alone or in combination with heat stress. At the same time, starch hydrolysis in leaves and seeds increased resulting in an accumulation of reducing sugars. Heat stress inhibited yield traits (seed number and seed weight per plant) more than drought stress, while drought stress reduced individual seed weights more than heat stress. The combined stress severely inhibited yield traits with less effect on the drought- and heat-tolerant genotypes. Drought stress inhibited the biochemical processes of seed filling more than heat stress, and the combined stress had a highly detrimental effect. A partial cross tolerance was noticed in drought and heat-tolerant lentil genotypes against the two stresses.

Rising temperatures are proving detrimental for various agricultural crops. Cool-season legumes such as lentil (Lens culunaris Medik.) are sensitive to even small increases in temperature during the reproductive stage, hence the need to explore the available germplasm for heat tolerance as well as its underlying mechanisms. In the present study, a set of 38 core lentil accessions were screened for heat stress tolerance by sowing 2 months later (first week of January; max/min temperature >32/20°C during the reproductive stage) than the recommended date of sowing (first week of November; max/min temperature <32/20°C during the reproductive stage). Screening revealed some promising heat-tolerant genotypes (IG2507, IG3263, IG3297, IG3312, IG3327, IG3546, IG3330, IG3745, IG4258, and FLIP2009) which can be used in a breeding program. Five heat-tolerant (HT) genotypes (IG2507, IG3263, IG3745, IG4258, and FLIP2009) and five heat-sensitive (HS) genotypes (IG2821, IG2849, IG4242, IG3973, IG3964) were selected from the screened germplasm and subjected to further analysis by growing them the following year under similar conditions to probe the mechanisms associated with heat tolerance. Comparative studies on reproductive function revealed significantly higher pollen germination, pollen viability, stigmatic function, ovular viability, pollen tube growth through the style, and pod set in HT genotypes under heat stress. Nodulation was remarkably higher (1.8–22-fold) in HT genotypes. Moreover, HT genotypes produced more sucrose in their leaves (65–73%) and anthers (35–78%) that HS genotypes, which was associated with superior reproductive function and nodulation. Exogenous supplementation of sucrose to in vitro-grown pollen grains, collected from heat-stressed plants, enhanced their germination ability. Assessment of the leaves of HT genotypes suggested significantly less damage to membranes (1.3–1.4-fold), photosynthetic function (1.14–1.17-fold) and cellular oxidizing ability (1.1–1.5-fold) than HS genotypes, which was linked to higher relative leaf water content (RLWC) and stomatal conductance (gS). Consequently, HT genotypes had less oxidative damage (measured as malondialdehyde and hydrogen peroxide concentration), coupled with a higher expression of antioxidants, especially those of the ascorbate–glutathione pathway. Controlled environment studies on contrasting genotypes further supported the impact of heat stress and differentiated the response of HT and HS genotypes to varying temperatures. Our studies indicated that temperatures >35/25°C were highly detrimental for growth and yield in lentil. While HT genotypes tolerated temperatures up to 40/30°C by producing fewer pods, the HS genotypes failed to do so even at 38/28°C. The findings attributed heat tolerance to superior pollen function and higher expression of leaf antioxidants.

Wheat (Triticum aestivum L.), with a large genome (16000 Mb) and high proportion (∼80%) of repetitive sequences, has been a difficult crop for genomics research. However, the availability of extensive cytogenetics stocks has been an asset, which facilitated significant progress in wheat genomic research in recent years. For instance, fairly dense molecular maps (both genetic and physical maps) and a large set of ESTs allowed genome-wide identification of gene-rich and gene-poor regions as well as QTL including eQTL. The availability of markers associated with major economic traits also allowed development of major programs on marker-assisted selection (MAS) in some countries, and facilitated map-based cloning of a number of genes/QTL. Resources for functional genomics including TILLING and RNA interference (RNAi) along with some new approaches like epigenetics and association mapping are also being successfully used for wheat genomics research. BAC/BIBAC libraries for the subgenome D and some individual chromosomes have also been prepared to facilitate sequencing of gene space. In this brief review, we discuss all these advances in some detail, and also describe briefly the available resources, which can be used for future genomics research in this important crop.

Chickpea is a cool season grain legume of exceptionally high nutritive value and most versatile food use. It is mostly grown under rain fed conditions in arid and semi-arid areas around the world. Despite growing demand and high yield potential, chickpea yield is unstable and productivity is stagnant at unacceptably low levels. Major yield increases could be achieved by development and use of cultivars that resist/tolerate abiotic and biotic stresses. In recent years the wide use of early maturing cultivars that escape drought stress led to significant increases in chickpea productivity. In the Mediterranean region, yield could be increased by shifting the sowing date from spring to winter. However, this is hampered by the sensitivity of the crop to low temperatures and the fungal pathogen Ascochyta rabiei. Drought, pod borer (Helicoverpa spp.) and the fungus Fusarium oxysporum additionally reduce harvests there and in other parts of the world. Tolerance to rising salinity will be a future advantage in many regions. Therefore, chickpea breeding focuses on increasing yield by pyramiding genes for resistance/tolerance to the fungi, to pod borer, salinity, cold and drought into elite germplasm. Progress in breeding necessitates a better understanding of the genetics underlying these traits. Marker-assisted selection (MAS) would allow a better targeting of the desired genes. Genetic mapping in chickpea, for a long time hampered by the little variability in chickpea's genome, is today facilitated by highly polymorphic, co-dominant microsatellite-based markers. Their application for the genetic mapping of traits led to inter-laboratory comparable maps. This paper reviews the current situation of chickpea genome mapping, tagging of genes for ascochyta blight, fusarium wilt resistance and other traits, and requirements for MAS. Conventional breeding strategies to tolerate/avoid drought and chilling effects at flowering time, essential for changing from spring to winter sowing, are described. Recent approaches and future prospects for functional genomics of chickpea are discussed. Chickpea: A valuable grain legumeChickpea (Cicer arietinum L.) is the only cultivated species within the genus Cicer. The crop is a selfpollinated diploid (2n = 2x = 16) with a relatively small genome (740 Mb, Arumuganathan & Earle, 1991). It is cultivated in arid and semi-arid areas around the world. With over 10 million ha under cultivation, chickpea is second only to common bean (Phaseolus vulgaris) and third in production among the legumes. The major producers India, Pakistan and Turkey contribute 65%, 9.5% and 6.7% respectively,

Deep and prolific root systems have been associated with enhanced avoidance of terminal drought stress in chickpea. This research evaluated the root traits of 257 recombinant inbred lines (RILs) derived from a cross between a breeding line with a large root system (ICC 4958) and an agronomically preferred variety (Annigeri) to assess the potential for identifying QTL for desirable root traits and to investigate the relationship between root traits, plant growth and seed yield under terminal drought stress. The root traits of field-grown chickpea RILs were measured using the monolith method during the 2001-2002 cropping season, while their shoot biomass and seed yield were evaluated during both 2000-2001 and 2001-2002 seasons. Significant genetic variation was observed amongst the RIL population for root length density, root dry weight and shoot dry weight at 35 days after sowing and for shoot biomass and seed yield at maturity. A linear relationship was observed between root dry weight and shoot dry weight at 35 days after sowing. The overall distribution of root length density and root dry weight among the RILs indicated that these traits are likely to be under polygenic control. The heritability of root dry weight was 0.27 and root length density was 0.23, compared to 0.49 for shoot dry weight at the same stage. The RILs exhibited a range of combinations of root size and seed yield, with a few RILs showing large root systems and high seed yield. However, there was no general correlation between seed yield and root size. High shoot biomass and harvest index contributed to high seed yield of the RILs. The implications for the molecular breeding of drought-avoidance root traits in chickpea are discussed.

UNC-104/KIF1A is a Kinesin-3 motor that transports synaptic vesicles from the cell body towards the synapse by binding to PI(4,5)P2 through its PH domain. The fate of the motor upon reaching the synapse is not known. We found that wild-type UNC-104 is degraded at synaptic regions through the ubiquitin pathway and is not retrogradely transported back to the cell body. As a possible means to regulate the motor, we tested the effect of cargo binding on UNC-104 levels. The unc-104(e1265) allele carries a point mutation (D1497N) in the PI(4,5)P2 binding pocket of the PH domain, resulting in greatly reduced preferential binding to PI(4,5)P2 in vitro and presence of very few motors on pre-synaptic vesicles in vivo. unc-104(e1265) animals have poor locomotion irrespective of in vivo PI(4,5)P2 levels due to reduced anterograde transport. Moreover, they show highly reduced levels of UNC-104 in vivo. To confirm that loss of cargo binding specificity reduces motor levels, we isolated two intragenic suppressors with compensatory mutations within the PH domain. These show partial restoration of in vitro preferential PI(4,5)P2 binding and presence of more motors on pre-synaptic vesicles in vivo. These animals show improved locomotion dependent on in vivo PI(4,5)P2 levels, increased anterograde transport, and partial restoration of UNC-104 protein levels in vivo. For further proof, we mutated a conserved residue in one suppressor background. The PH domain in this triple mutant lacked in vitro PI(4,5)P2 binding specificity, and the animals again showed locomotory defects and reduced motor levels. All allelic variants show increased UNC-104 levels upon blocking the ubiquitin pathway. These data show that inability to bind cargo can target motors for degradation. In view of the observed degradation of the motor in synaptic regions, this further suggests that UNC-104 may get degraded at synapses upon release of cargo.

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