Engineering Cold Stress Tolerance in Crop Plants

Plants respond with changes in their pattern of gene expression and protein products when exposed to low temperatures. Thus ability to adapt has an impact on the distribution and survival of the plant, and on crop yields. Many species of tropical or subtropical origin are injured or killed by non-freezing low temperatures, and exhibit various symptoms of chilling injury such as chlorosis, necrosis, or growth retardation. In contrast, chilling tolerant species are able to grow at such cold temperatures. Conventional breeding methods have met with limited success in improving the cold tolerance of important crop plants involving inter-specific or inter-generic hybridization. Recent studies involving full genome profiling/ sequencing, mutational and transgenic plant analyses, have provided a deep insight of the complex transcriptional mechanism that operates under cold stress. The alterations in expression of genes in response to cold temperatures are followed by increases in the levels of hundreds of metabolites, some of which are known to have protective effects against the damaging effects of cold stress. Various low temperature inducible genes have been isolated from plants. Most appear to be involved in tolerance to cold stress and the expression of some of them is regulated by C-repeat binding factor/ dehydration-responsive element binding (CBF/DREB1) transcription factors. Numerous physiological and molecular changes occur during cold acclimation which reveals that the cold resistance is more complex than perceived and involves more than one pathway. The findings summarized in this review have shown potential practical applications for breeding cold tolerance in crop and horticultural plants suitable to temperate geographical locations

Breeding strategies for improving growth and yield under waterlogging conditions in maize: A review

Waterlogging, caused by flooding, excessive rains and poor drainage is a serious abiotic stress determining crop productivity worldwide. Maize (Zea mays L) is a basic food grain in many areas and several cultures and is culti- vated under much diverse agro-climatic zones extending from subtropical to cooler temperate regions. Therefore, the crop remains open to varied types of biotic as well as abiotic stresses. Among various abiotic stresses, water- logging is one of the most important constraints for maize production and productivity. Breeding for improved wa- terlogging tolerance includes modification of plant morphology, use of tolerant secondary traits and development of resistant varieties through conventional breeding and biotechnological approaches. A successful programme in conventional breeding should involve the integration of several criteria into one selection index and also successful breeding programmes for improved tolerance to submergence stress frequently combine two or more breeding strategies. Marker assisted selection (MAS) is an effective approach to identify genomic regions of crops under stress and construction of molecular linkage maps enable carry out pyramiding of desirable traits to improve sub- mergence tolerance through MAS

Participatory rural appraisal and farmers’ perception about common bean varieties in temperate Kashmir

Present investigation was undertaken during 2012 to 2014 in which 54 genotypes, both pole and bush type of Common beans (Phaseolus vulgaris) were selected among a number of germplasm lines, land races and research material in order to generate information on the farmer’s’ perception about the Common bean varieties. Participatory rural appraisal was conducted in 32 villages of Kashmir through a broad questionnaires comprising of questions pertaining to the socio-economic conditions, farming systems, production constraints and varietal preferences of the common bean. The Participatory Rural Appraisal results revealed that common bean is generally grown as a rainfed crop (70 %) and is intercropped with maize/ potato/vegetable and merely as sole crop (20.66 %). Low yielding varieties and diseases (68.27 %) are considered as major challenges in the success of common bean crop, while as red colour with kidney shaped types (50 %) are highly being preferred as a pulse crop. The exercise of Participatory Rural Appraisal was carried out to generate basic information by assessing the need based constraints and devise the target breeding approach, by taking into consideration all constraints and also devise future breeding programme. A successful PRA provides the information needed to specify the characteristic in a new variety regarding its physical environment and the existing varietal diversity. For a breeding program, well applied Participatory Rural Appraisal techniques or customer profiling results in better client orientation and makes possible efficient goal setting or product design. Successful PRA provides everything that could be included in the full design specification of a new crop variety

Bio-techniques for improvement of qualitative and quantitative traits in walnut (Juglans regia)

Walnut, Juglans regia (L.) is an economically significant plant for its immense nutritive and economic value. The breeding character of walnut has lent it a wide diversity in genetic characteristics. The principal vegetative and common traditional agronomic traits together with biochemical characterization i.e., karyotyping and isoenzyme expression have been the early research methods. However, these techniques are time-consuming and susceptible to the environmental variations. Literature is meager in the distribution, applied applications in general and the use of agriculture biotechnology in particular in case of walnut plants. The bio-techniques like molecular markers are adequate in number and there is little or no diversity in the method employed for research on walnuts. Despite basic research method, the organization of information, its retrieval and presentation structures, form elaboration experienced immense advancement via molecular markers such as RFLP, ISSR, RAPD AFLP, SSR and SNP. This appraisal in its first part provides detailed information regarding the present scenario of data on biogeographical distribution, health benefits of walnut worldwide and current applications in the agroforestry management, biochemical evaluations and applied uses of a walnut tree which is relevant for both basic and applied research. The review in its second part sheds light on the application of sophisticated agricultural biotechnology techniques such as use of molecular markers to evaluate, realize the full potential of walnut for increasing its quality, quantity and for its sustainable production which cannot be obtained through usual breeding techniques to meet the demands of a projected world population

Genotypic and morphological diversity analysis in high altitude maize (Zea mays L.) inbreds under Himalayan temperate ecologies

The present investigation was carried out to generate information on genetic divergence of maize (Zea mays L.) inbreds and to identify elite lines to develop potential hybrids for high altitude ecologies. Data were recorded for thirteen (13) quantitative traits viz. germination (%), root depth, shoot length, days to 50 % pollen shed, days to 50% silking, plant height, ear height, ear length, ear girth, number of kernels per row, 100 seed weight, grain yield per plant. The tested genotypes expressed significant variability with high estimates of heritability (broad sense) for all the traits revealing that these traits are amenable to genetic improvement. Grain yield per plant exhibited positive and significant correlation with plant height, ear height, ear width, number of kernels per row, number of kernel rows and 100 seed weight at both the levels which exhibit a strong possibility for improvement of grain yield per plant by selection for these traits. Genetic divergence based on thirteen quantitative traits grouped thirty maize inbred lines into four clusters as per Mahalanobis D2 analysis employing Tocher’s method which revealed wide diversity in elite genotypes owing to the involvement of diverse parental lines in the hybridization programme. Grain yield per hectare was the main factor contributing to total divergence (41.16%) which needs to be considered for highlighting clusters to be chosen for the purpose of further selection

Review article: Quality protein maize (QPM): Genetic

Cereals are the only source of nutrition for one-third of the world’s population especially in developing and underdeveloped nations of Sub-Saharan Africa and South-east Asia. The three major cereals, rice, wheat and maize constitute about 85% of total global cereals production amounting to about 200 million tonnes of protein harvest annually at an average of 10% protein content, out of which a sizeable proportion goes into human consumption (Shewry, 2007). A major concern in case of developing nations is that in most cases, a single cereals crop is the major food staple and as such the nutritional profile of cereal crops assumes great significance. Grain protein content of cereals has a very narrow range with rice (5.8-7.7%), maize (9-11%), barley (8-15%) and wheat (7-22%) as reported by various workers. In many developing countries of Latin America, Africa and Asia, maize is the major staple food and often the only source of protein. At global level, maize accounts for 15% of proteins and 20% of calories in world food diet. But unfortunately, the nutritional profile of maize is poor as it is deficient in essential amino acids such as lysine, tryptophan and methionine due to a relatively higher proportion of prolamines in maize storage proteins which are essentially devoid of lysine and tryptophan. The reason concerning this is that lysine, tryptophan and threonine are the limiting amino acids in human beings and non-ruminants. Maize is also an important component of livestock feed especially in developed nations where 78% of total maize production goes into livestock feed. Therefore, breeding strategies aimed at improving the protein profile of maize will go a long way in reducing prevalence and persistence of malnutrition in developing world