Soil salinity is a major threat to crop productivity and quality worldwide. In order to reduce the negative effects of salinity stress, it is important to understand the genetic basis of salinity ...tolerance. Identifying new salinity tolerance QTL or genes is crucial for breeders to pyramid different tolerance mechanisms to improve crop adaptability to salinity. Being one of the major cereal crops, wheat is known as a salt-sensitive glycophyte and subject to substantial yield losses when grown in the presence of salt. In this study, both pot and tank experiments were conducted to investigate the genotypic variation present in 328 wheat varieties in their salinity tolerance at the vegetative stage. A Genome-Wide Association Studies (GWAS) were carried out to identify QTL conferring salinity tolerance through a mixed linear model. Six, five and eight significant marker-trait associations (MTAs) were identified from pot experiments, tank experiments and average damage scores, respectively. These markers are located on the wheat chromosomes 1B, 2B, 2D, 3A, 4B, and 5A. These tolerance alleles were additive in their effects and, when combined, increased tolerance to salinity. Candidate genes identified in these QTL regions encoded a diverse class of proteins involved in salinity tolerance in plants. A Na
+
/H
+
exchanger and a potassium transporter on chromosome 5A (IWB30519) will be of a potential value for improvement of salt tolerance of wheat cultivars using marker assisted selection programs. Some useful genotypes, which showed consistent tolerance in different trials, can also be effectively used in breeding programs.
Soil salinity is one of the major abiotic stresses restricting plant growth and development. Application of plant growth regulators (PGRs) is a possible practical means for minimizing ...salinity-induced yield losses, and can be used in addition to or as an alternative to crop breeding for enhancing salinity tolerance. The PGRs auxin, cytokinin, nitric oxide, brassinosteroid, gibberellin, salicylic acid, abscisic acid, jasmonate, and ethylene have been advocated for practical use to improve crop performance and yield under saline conditions. This review summarizes the current knowledge of the effectiveness of various PGRs in ameliorating the detrimental effects of salinity on plant growth and development, and elucidates the physiological and genetic mechanisms underlying this process by linking PGRs with their downstream targets and signal transduction pathways. It is shown that, while each of these PGRs possesses an ability to alter plant ionic and redox homeostasis, the complexity of interactions between various PGRs and their involvement in numerous signaling pathways makes it difficult to establish an unequivocal causal link between PGRs and their downstream effectors mediating plants' adaptation to salinity. The beneficial effects of PGRs are also strongly dependent on genotype, the timing of application, and the concentration used. The action spectrum of PGRs is also strongly dependent on salinity levels. Taken together, this results in a rather narrow "window" in which the beneficial effects of PGR are observed, hence limiting their practical application (especially under field conditions). It is concluded that, in the light of the above complexity, and also in the context of the cost-benefit analysis, crop breeding for salinity tolerance remains a more reliable avenue for minimizing the impact of salinity on plant growth and yield. Further progress in the field requires more studies on the underlying cell-based mechanisms of interaction between PGRs and membrane transporters mediating plant ion homeostasis.
Waterlogging is an environmental stress, which severely affects barley growth and development. Limited availability of oxygen in the root zone negatively affects the metabolism of the whole plant. ...Adventitious roots (AR) and root cortical aerenchyma (RCA) formation are the most important adaptive traits that contribute to a plant's ability to survive in waterlogged soil conditions. This study used a genome-wide association (GWAS) approach using 18,132 single nucleotide polymorphisms (SNPs) in a panel of 697 barley genotypes to reveal marker trait associations (MTA) conferring the above adaptive traits. Experiments were conducted over two consecutive years in tanks filled with soil and then validated in field experiments. GWAS analysis was conducted using general linear models (GLM), mixed linear models (MLM), and fixed and random model circulating probability unification models (FarmCPU model), with the FarmCPU showing to be the best suited model. Six and five significant (approximately -log
(
) ≥ 5.5) MTA were identified for AR and RCA formation under waterlogged conditions, respectively. The highest -log
(
) MTA for adventitious root and aerenchyma formation were approximately 9 and 8 on chromosome 2H and 4H, respectively. The combination of different MTA showed to be more effective in forming RCA and producing more AR under waterlogging stress. Genes from major facilitator superfamily (
) transporter and leucine-rich repeat (
) families for AR formation, and ethylene responsive factor (
) family genes and potassium transporter family genes for RCA formation were the potential candidate genes involved under waterlogging conditions. Several genotypes, which performed consistently well under different conditions, can be used in breeding programs to develop waterlogging-tolerant varieties.
Tomato (
L.) is a popular nutritious vegetable crop grown in Malaysia and other parts of the world. However, fungal diseases such as anthracnose pose significant threats to tomato production by ...reducing the fruit quality and food value of tomato, resulting in lower market prices of the crop globally. In the present study, the etiology of tomato anthracnose was investigated in commercial tomato farms in Sabah, Malaysia. A total of 22 fungal isolates were obtained from anthracnosed tomato fruits and identified as
species, using morphological characteristics. The phylogenetic relationships of multiple gene sequence alignments such as internal transcribed spacer (ITS), β-tubulin (
), glyceraldehyde 3-phosphate dehydrogenase (
), actin (
), and calmodulin (
), were adopted to accurately identify the
species as
. The results of pathogenicity tests revealed that all
isolates caused anthracnose disease symptoms on inoculated tomato fruits. To our knowledge, the present study is the first report of tomato anthracnose caused by
in Malaysia. The findings of this study will be helpful in disease monitoring, and the development of strategies for effective control of anthracnose on tomato fruits.
The potato varieties, Asterix, Granola and Diamant produce microtubers that are in high demand in Bangladesh. To achieve the full yield potentials of these varieties, an experiment was carried out to ...determine the efficient protocol for microtuberization. The results showed a wide range of variation in the response of the potato varieties to the addition of chlorocholine chloride (2-chloroethyl)-trimethylammonium chloride (CCC) and 6-benzylaminopurine (BAP) to the microtuberization medium. Potato varieties Asterix and Diamant were more efficient to microtuberization.
Crops specific proper concentration of micronutrient application is necessary to improve the yield and quality of crops. Therefore, an experiment was conducted to identify the optimum dose of boron ...for groundnut plant. Six level of boron (B) application, B
0
(0 ppm), B
1
(0.5 ppm), B
2
(1 ppm), B
3
(2 ppm), B
4
(4 ppm) and B
5
(8 ppm) were evaluated. Photosynthetic rate, transpiration and stomatal conductance were increased for boron application but leaf vapor pressure deficit decreased. Physiological growth parameters, yield and yield contributing character, and shelling percentage was highest for B
3
. The values of biochemical traits including protein, oil and vitamin E content were higher for B
4
. Thus, leaf gas exchange showed that boron can be used to culture groundnut as it provides high yield and biochemical properties.
Boron application at proper concentration is necessary to enhance the leaf gas exchange, physiological growth, reproductive development and nutritional improvement of crops. Therefore, an experiment ...was conducted to study the effects of boron to evaluate the effect on the leaf gas exchange, reproductive development, physiological and nutritional changes of peanut. Treatments comprised six levels of boron (B), viz., B
1
(0 ppm), B
2
(0.5 ppm), B
3
(1 ppm), B
4
(2 ppm), B
5
(4 ppm) and B
6
(8 ppm). Results revealed that the vegetative growth, physiological growth parameters, leaf gas exchange, reproductive characters, peg strength, shelling (%) and nutritional elements were increased for boron application. Some vegetative, physiological and reproductive traits are positively correlated with each other. Thus, this finding showed that boron can be used to culture peanut as it provides high yield and nutritional properties.
Boron is an important micronutrient that enhances reproductive growth of crops such as groundnut. Light also plays an important role for pegging of groundnut. There has been little information on the ...application of boron and light in groundnut in Bangladesh. A field experiment was conducted to study the effects of boron and light on the reproductive development of two groundnut cultivars. Treatments considered as two groundnut cultivars, viz., ‘Dhaka-1 (C1)’ and ‘BARI Chinabadam-8 (C2)’, three levels of boron (B), viz., 0-kg B ha−1 (B0), 1-kg B ha−1 (B1) and 2-kg B ha−1 (B2), and two levels of light, viz., normal day light (≈12-h light) and normal day light + 6-h extended red light at night (≈18-h light). Result revealed that the reproductive development, yield and shelling percentage of groundnut were markedly increased with the application of B. Due to imposition of light all of reproductive units increased but decrease number of pods and pod yield. The highest reproductive unit and yield were observed from ‘BARI Chinabadam-8’. Therefore, reproductive development could be improved by application of boron in improved cultivars (BARI Chinabadam-8) but not for under extended light.
Light and boron play a significant role in the physiological growth and yield of crops such as groundnut. Even so, there has been little information on the application of boron in groundnut, while no ...information is available in Bangladesh regarding the imposition of light in groundnut. Therefore, two field experiments were conducted in order to evaluate the physiological growth and seed yield of groundnut. Treatments included two levels of light, viz., L0 = normal day length (≈12-h light) and L = normal day length + 6-h extended light at night (≈18-h light); three levels of boron, viz., 0-kg B ha-1 (B0), 1-kg B ha-1 (B1) and 2-kg B ha-1 (B2), and two groundnut varieties, viz., V1 = ‘Dhaka-1’ and V2 = ‘BARI Chinabadam-8’. The results obtained from the experiment revealed that the highest LAI, LAR, LMR and RWR were recorded in L, B2 and V2 variants, while NAR was the highest in L0 and B0. Moreover, it was noted an inconsistent result for RGR found for boron application. Based on the results, it could be concluded that boron is one of the factors responsible for higher yield of groundnut; nevertheless, under the extended light, it is not possible to get the highest yield.
Boron is an important micronutrient that enhances vegetative growth and yield of crops, like peanut. Light also plays an important role in pegging of peanut. There has been little information ...regarding the application of boron and light in peanut in Bangladesh. Therefore, a field experiment was conducted to study the response of boron and light on morph-physiology and pod yield of two peanut varieties. Treatments considered two peanut varieties, namely, Dhaka-1 and BARI Chinabadam-8, three levels of boron (B), namely, 0-kg B ha−1 (B0), 1-kg B ha−1 (B1), and 2-kg B ha−1 (B2), and two levels of light, namely, normal day light (≈12 h light) and normal day light + 6 h extended red light at night (≈18 h light). Result revealed that days to first-last emergence and days to first-50% flowering took shorter times and vegetative growth, pods dry weight plant−1, pod yield, and germination were markedly increased with the application of boron. Vegetative growth and germinations were significantly increased in light, but the lowest leaf area, pods dry weight plant−1, and pod yield were found in light. Without germination, the highest vegetative growth, reproductive unit, and pod yield were observed from BARI Chinabadam-8. Days to first-last emergence, days to first-50% flowering, and number of branches plant−1 were found linearly related to pod yield.
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