Gene expression pattern of K transporter GhHAK5 gene of potassium efficient and in-efficient cotton cultivars based on morphological physiognomies as affected by potassium nutrition and reduced irrigation

Background Under K deficiency the uptake and distribution pattern in plant cells is mediated through different transport proteins and channels which were controlled by specific gene family.Therefore,a hydroponic experiment was conducted under control condition for testing the gene expression pattern of the K transporter under adequate and low K supply levels.After that,a 2-year field experiment was conducted to evaluate five selected cotton cultivars(four K-efficient cultivars,viz.,CIM-554,CYTO-124,FH-142,IUB-2013,and one K non-efficient,BH-212) screened from the initial hydroponics culture experiment and two levels of potassium(0 K_(2)O kg·ha^(-1) and 50 K_(2)O kg·ha^(-1)) were tested under reduced irrigation(50% available water content;50 AWC) and normal irrigation conditions(100% available water content;100 AWC).Result Results revealed that the transcript levels of GhHAK5aD in roots were significantly higher in K^(+) efficient cultivars than that in K^(+) non-efficient cultivars.The GhHAK5aD expression upon K^(+) deficiency was higher in roots but lower in shoots,indicating that GhHAK5aD could have a role in K^(+) uptake in roots,instead of transport of K^(+) from root to shoot.Similarly,under field conditions the cultivar FH-142 showed an increase of 22.3%,4.9%,2.4%,and 1.4% as compared with BH-212,IUB-2013,CYTO-124,and CIM-554,respectively,in seed cotton yield(SCY) with K application under reduced irrigation conditions.With applied K,the FH-142 showed an increase in net photosynthetic rate by 57.3% as compared with the rest of the cultivars under reduced irrigation over K control.However,the overall performance indicators of K-efficient cultivars like FH-142,CYTO-124,CIM-554,and IUB-2013 were better than BH-212(K in-efficient) under reduced irrigation conditions with applied K at 50 kg·ha^(-1).Fiber quality trait improved significantly with K application under water deficit.The increase in micronaire was 3.6%,4.7%,7.8%,3.4%,and 6.7% in BH-212,IUB-2013,CIM-554,CYTO-124,and FH-142,respectively,with K application at 50 kg·ha^(-1) over without K application under reduced irrigation conditions during the cotton growing season.Similarly,the cultivars FH-142 increased by 12% with K application under reduced irrigation as compared with other cultivars.The performance of K-efficient cultivars under reduced irrigation conditions was 30% better in SCY and quality traits with the application of K at 50 kg·ha^(-1) as compared with K-non-efficient cultivars.Similarly,water use efficiency(WUE)(40.1%) and potassium use efficiency(KUE)(20.2%) were also noted higher in case of FH-142 as compared with other cultivar with K application under reduced conditions.Conclusion Higher expression of GhHAK5aD gene was observed in K-efficient cultivars as compared with K-nonefficient cultivars in roots indicates that GhHAK5aD may be contributing to genotypic differences for K^(+) efficiency in cotton.K-efficient cotton cultivars can be used for the low-K environments and can also be recommended for general cultivars.

Differences in the Efficiency of Potassium (K) Uptake and Use in Barley Varieties

Screening of crop genotypes with high K efficiency plays a fundamental role in understanding their physiological mechanisms. In this study, pot culture experiment was conducted to reveal the differences in uptake and use of K among 56 barley varieties. The coefficient of variation （CV） of K uptake （Ku） and K dry matter production index （KDMPI） of these varieties were higher than other indices and both Ku and KDMPI were significantly different among the barley varieties. Furthermore, Ku and KDMPI were positively correlated with dry matter weight （DMW） during the whole growth period; K use efficiency （KUE） and K harvesting index （KHI） were significantly related to dry grain weight （DGW） at maturing stage. Through cluster of these indices, Sandrime and AC Westech were found to be the most K-efficient and K-inefficient genotypes of barley, respectively. Significant differences were observed in uptake and use capacity of K between the two genotypes. During the whole growth period, Ku, K dry matter production efficiency （KDMPE）, KDMPI and DMW of the K- efficient genotype were found to be 1.5-1.8, 1.4-2.3, 2.1-3.9, and 1.7-2.1 times higher than those of the K-inefficient genotype, respectively, and at maturing stage, DWG, KUE, and KHI of efficient genotype were higher than those of the inefficient one. The results also showed that Sandrime was the most efficient candidate among the tested varieties for K efficiency and further studies should be conducted to investigate its physiological and biochemical characteristics.

Preparation, Characterization and Evaluation of Efficacy of Phosphorus and Potassium Incorporated Nano Fertilizer

Phosphorus and Potassium incorporated nano fertilizer were prepared using zeolite as a carrier material at a laboratory scale. X-ray diffraction (XRD) analysis was done for the characterization and confirmation of the incorporation. Chemical analyses also indicate the sorption of fertilizer material into zeolite. An in vitro incubation study was conducted for 30 days at field moisture condition to see the release of the fertilizer materials and was compared with a conventional fertilizer. The release pattern of nutrients from either source showed a substantial decreasing trend with time although the release of P and K was higher for nano fertilizer than the conventional one. A pot culture experiment with Ipomoea aquatica (Kalmi) was also conducted to see the efficacy of the nano fertilizer in the growth promotion of the plant. Analysis showed higher accumulation of P and K in plants grown with nano fertilizer. Post-effect of nano fertilizer application in soil showed better pH, moisture, CEC, available P and K under nano fertilizer treatment than the conventional fertilizer.