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Cotton crop is infected by single stranded DNA viruses (Family, Geminiviridae) in Pakistan. Due to changing global climate, which favors the whitefly (insect vector) growth and reproduction, the spread of cotton leaf curl disease is increasing at an alarming rate. Various approaches are being used to diagnose the ssDNA viruses in cotton. One step PCR protocol was established to identify the three viruses, namely cotton leaf curl Multan virus (CLCuMuV), Burewala strain of Kokhran virus (CLCuKo-Bur) and cotton leaf curl Kokhran virus (CLCuKoV). Thirty eight genotypes were screened on the basis of symptoms and molecular diagnosis. Out of 38 genotypes, 13 were positive for CLCuMuV, 24 were positive for Burewala strain and one was positive for both CLCuMuV and CLCuKoV-Bur strain. However, none of the samples was positives for cotton leaf curl Kokhran virus. Our experiments have established one step guide PCR for screening of cotton germplasm for major cotton infecting viruses. This diagnostic assay will promote the breeding programs for the development of resistant cotton varieties against cotton leaf curl disease (CLCuD) in Pakistan. [ABSTRACT FROM AUTHOR]

A major drawback of waste water irrigation to vegetables is the presence of lethal disease causing bacteria and the risk of their transmission to the tomato fruit. The presence of S. enterica subspecies enterica in fruiting bodies of tomato plant was traced, irrigated with contaminated waste water. Molecular and cultural diagnosis of S. enterica subsp. enterica was carried out in tomato fruits after contaminated waste water irrigation to determine its transmission from water to tomato fruits. Sixteen genotypes were irrigated with waste water from germination to maturity. Tomato fruits were sampled and their flesh was used as inoculums for culturing the bacteria. No bacterial infection was detected in two genotypes while remaining fourteen accessions were found positive for bacterial growth in the culture. PCR amplification of bacterial 16srRNA was observed in all 14 genotypes depicting the bacterial infection in these fruits. But the diagnostic primers of S. enterica were amplified only in the fruits of two genotypes out of total 16. These Results showed that 87.5% genotypes were free of S. enterica subsp. enterica contamination, depicting that most of the time pathogen was physiologically blocked from gaining access to the tomato fruit. It further confirmed the presence of variability for the potential of bacterial transmission from root to fruit in the tomato genotypes. The advantage of this variability can be harnessed in the form of breeding such genotypes, which present strong physiological barrier and defence system for the bacterial transmission to the tomato fruit. © 2015 Friends Science Publishers [ABSTRACT FROM AUTHOR]

The biochemical basis of pigmentation has been well studied in naturally colored cotton but little is known about the molecular basis of color development in cotton fibers. The differences in pigmentation between brown, green and white cotton fiber can be mined by the molecular study of structural genes of flavonoid biosynthesis pathway. The transcriptome analysis of five flavonoid biosynthesis related structural genes, encoding chalcone isomerase (GhCHI), flavanone 3-hydroxylase (GhF3H), dihydroflavonol 4-reductase (GhDFR), anthocyanidin synthase (GhANS), and anthocyanidin reductase (GhANR) was performed at two fiber developmental stages i.e. 10 DPA and 20 DPA in brown, green and white cotton. The transcript level of all structural genes was higher in brown cotton fiber as compared to green and white at both 10 DPA (days post anthesis) and 20 DPA. The decline in the transcript level of all structural genes except GhANS was observed at 20 DPA as compared to 10 DPA. The transcript accumulation of GhANS was negligible in green and white cotton fibre at both stages. Correlating these findings with the flavonoid biosynthetic pathway revealed that GhANR and its substrate GhANS are crucial for the synthesis of proanthocyanadines, which is a brown pigment and transcripts of structural genes are directly proportional to the brown pigment. In conclusion, GhANS gene is strongly associated to the brown color development and modulation in the transcript level of this gene could improve the pigmentation of brown cotton fibers. © 2015 Friends Science Publishers [ABSTRACT FROM AUTHOR]

The genetic resistance in high yielding pea cultivars against powdery mildew provides a cost effective and reliable strategy to reduce the yield losses and save quality of the harvest. The dependable selection of powdery mildew resistant source(s) is the most crucial step in breeding for disease resistance. The efficiency of a simple, reliable and reproducible screening method on detached leaves of pea under controlled environmental condition was evaluated in comparison with field screening under natural conditions. The detached leaf assay coupled with microscopic quantification of susceptibility percentage (%S) appeared ten times more precise and reproducible than field screening based on visual observation of percentage of leaf area affected with disease. A new 0-5 microscopic disease scale proposed here is more robust and stringent for making selections for powdery mildew resistant parents and effectively challenging the segregating populations against different isolates of Erysiphe pisi simultaneously. The disease scale is based on susceptibility percentage (%S) as a function of percentage of germinated conidia with mycelial growth. For making more precise calculations non germinated conidia without germ tube were not taken in to account. The use of detached leaf assay and microscopic quantification of conidia has provided a simple and reliable screening method to clearly distinguish between escape and resistance mechanisms and the results are not prone to fluctuations in environmental conditions. The assay results were highly correlated (0.993) with the disease severity of whole plants under field conditions; moreover, dCAPS markers have also validated the assay results. Two pea genotypes (It-96 and No. 267) have been selected as highly resistant to powdery mildew, which could be used as a source for breeding disease resistant pea cultivars. [ABSTRACT FROM AUTHOR]

Mutagenesis has been used to a good extent to induce genetic variability in plant species to achieve the desired genetic variability. To attain maximum useful mutation density per unit genome and comparative effectiveness of γ-rays and Ethyl methanesulfonate (EMS), optimal dose for treatment is the key to success. This study focuses on the development of kill curve in three cotton species (Gossypium arboreum, G. barbadense and G. hirsutum). Four genotypes from each of these Gossypium species were treated with eight varying levels of EMS (0.1 to 0.8%) and two doses of γ-rays (100 to 800 Gy) for kill curve analysis. The data collected on germination percentage, plant height, number of bolls/plant, boll weight, lint yield and its percentage were analyzed and significant interaction among species, genotypes, mutagens and levels of mutagens was observed for all traits under study. Morphologically unusual mutants (rudimentary sparse leaves pattern and broad leaf shape) were also identified from M1 generations of cotton genotypes. Optimal mutagenic doses were calculated based on survival rate and seed viability, which were considered useful in developing cotton mutagenized populations for forward and reverse genetic studies. EMS observed to be more effective than γ-rays as it generated overall more number of mutants, while later caused higher physical injury in all cotton species. [ABSTRACT FROM AUTHOR]

Drought tolerance is the major area of thrust nowadays, due to the water scarcity and climate change scenario, around the globe. Looking for the novel cotton germplasm tolerant to drought is an important breeding objective of the major breeding programs. On the basis of these grounds, 42 cotton varieties were evaluated for their genetic potential to perform under limited water conditions (60% field capacity). The germplasm was subjected to the seedling stage drought stress, to observe genetic variation within germplasm for various traits related with drought stress viz. shoot length (cm), root length (cm), excise leaf water loss (ELWL) and relative water contents (RWC). These traits were used as stress indicators and significant variation was observed for these estimates. Among the seven tolerant accessions, DPL-26 and 149F were identified as the highly tolerant due to their least SSI estimates for most of the characters studied. Likewise among the susceptible lines, FH-1000 and NF-801 were identified as highly susceptible. Our studies showed the presence of genetic variability for the trait of interest and it exhibits its potential for exploitation in the future breeding for drought tolerance. © 2015 Friends Science Publishers [ABSTRACT FROM AUTHOR]

This research work was planned to screen a part of cotton germplasm to find out their salt tolerance potential at seedling stage measuring root length, shoot length, root fresh weight, root dry weight, root dry weight and shoot dry weight. A control and two levels of NaCl (10 & 20 dS m-1) and 50 cotton genotypes in completely randomized design were used. Data indicated that there was significant reduction in all seedling traits. It was also observed that 24 genotypes could not show even emergence at 20 dS m-1 salinity level. Moderate to high genetic variability was observed in all traits at all levels of salinity except at relative salinity of 10 dS m-1. High heritability and high genetic advance was also found for most of the traits. Some genotypes were ranked top on the basis of root length, while others performed well on the basis of shoot dry weight. Thus, to get rid of this complication, selection index was performed by giving an equal weight to all the seedling traits studied. As a result, top 6 genotypes (NIAB-999, CIM-707, NIAB-78, MNH-93, CIM-446 & CIM-443) performing well at 20 dS m-1 were declared salt tolerant. [ABSTRACT FROM AUTHOR]

Cell suspension cultures were initiated from six month old ovule-derived embryogenic calli of two Citrus species named Citrus aurantifolia (Christm.) Swingle cultivar Sweet lime and Citrus reticulata Blanco cultivar Kinnow. The growth rate of cells was observed on two different media MT basal medium + 0.5 g L-1 malt extract (EME) and MT containing half strength NH4NO3 and KNO3, supplemented with 1.55 g L-1 glutamine and 0.75 g L-1 KCl (H+H). Kinnow and Sweet lime cells showed a sigmoidal growth pattern on (H+H) and (EME) liquid media, when PCV was plotted against time. The logarithmic phase of cells started from 4th to 10th day and after that a stationary phase observed in cells with elongated vacuoles. This indicated that citrus cells active phase started soon after subculture and ends after two weeks. These embryogenic suspension cultures were later used for protoplast isolation which is a key step towards somatic hybridization. [ABSTRACT FROM AUTHOR]

Soil salinity among other abiotic stresses is a major threat to cultivated land. Breeding salt tolerant cultivars has always been thought to be an effective and cheaper way to overcome salinity problem. Salt tolerant and salt sensitive wheat accessions were hybridized to develop genetic material to investigate inheritance of salt tolerance based on early seedling, adult plant and physiological responses. Salt tolerance in low salinity appeared to be a complex polygenic trait. However, genetic models for most responses were poor fit in high salinity and suggested further investigations. Differences in gene expressions in different NaCl concentrations appeared to be due to different gene regulation or interaction and/or involvement of additional or hidden genes. Both additive and non-additive gene effects required to be considered while designing of breeding programme for improving salt tolerance in wheat and in the statistical model used to find QTL for the salt tolerance. This QTL couple with recurrent selection for specific combining ability of the 4WLRG/1-8 with an excellent cultivar of wheat appears to be a good salt tolerant breeding strategy. © 2014 Friends Science Publishers [ABSTRACT FROM AUTHOR]