JPAA

Exploration of genetic diversity and drought tolerance potential of bread wheat genotypes at seedling stage using the multivariate analyses tools

2023-09-12T08:12:30+05:00

Drought stress is one of the major limiting factors in plant growth. The endeavor of the present research was to identify bread wheat drought-tolerant genotypes by screening on the basis of seedling characteristics. The experiment was conducted during the cropping season (2021-2022) in the wire house of the Department of Plant Breeding & Genetics, Faculty of Agriculture & Environment, The Islamia University of Bahawalpur, Pakistan. Fifty-five genotypes were screened at the seedling stage under normal and drought stress conditions. Three treatments (T1, T2 and T3) were used with different polyethylene glycol (PEG-6000) solution concentrations i.e., (T1 was the controlled condition, T2 had 15% PEG solution, and T3 had 25% PEG solution). The results depicted the presence of significant differences among the genotypes related to drought tolerance and genetic diversity in response to the stress conditions using various morpho-physiological traits. Shoot fresh weight and chlorophyll content index were positively correlated under all treatments. Thus, the selection of these traits at the seedling stage would improve genetic gain for drought tolerance. Based on the results of principal component analysis (PCA), the promising genotypes identified were G19 (T1), G47 (T2) and G35 (T3). The identified traits could well serve as potential drought tolerance indicators and identified genotypes can be further utilized in future wheat breeding programs to develop high-yielding and drought-resilient genotypes.

Effect of crop maturity condition and operating factors on the threshing performance of wheat thresher

2023-09-12T07:45:51+05:00

Sustainable agriculture is majorly related to mechanized agriculture systems. The outdated threshing operations lead to a negative impact on wheat threshing performance and contribute to overall post-harvest losses. Mechanized agriculture could produce encouraging results for productivity enhancement including grain damage reduction, better efficiency, and improved threshing technology. The objective of this research study was to assess the effect field operating conditions in the farmers field and maturity characteristics of wheat on threshing performance of locally developed wheat thresher during wheat seasons 2017-18. The wheat thresher produced significantly higher results for wheat (Faisalabad-2008) with the mean threshing efficiency (98.83%) and grain cleaning efficiency (98.93%) at crop moisture (16.6%) and feeding of 52 kg/min. while the least grain breakage percentage (0.75%) was found. The quantity of grain lost in wheat straw was found to be minimum 0.16% at the feeding rate of 47 kg/min and mid harvesting stage (16.6%). The wheat thresher chopped straw size was (2.28 cm) accurate and uniform at moisture content 16.6% (mid harvesting stage) while the straw chopping was non-uniform and irregular at late harvesting stage of wheat crop (1.93cm). The maximum fuel consumption and energy utilized were calculated 6.71 L/h and 76.57 kWh respectively for wheat variety Lasani-2008 (V₃) at feeding rate FR₃, 52 kg/min. The results revealed that the crop moisture content and feeding rate has significant effects on the threshing efficiency, cleaning efficiency and grain damage.

Combining ability studies of high-temperature stress tolerant attributes of advance lines of spring wheat under a hot and dry climate of Bhakkar

2023-09-12T07:04:31+05:00

An expected increase in world temperature requires us to better know the scope of heat stress experienced by plants. So, we highlighted the combining ability of wheat plant to combine successfully with another wheat plant, resulting desirable traits in next generation and it also provides information about the controlling of genetic mechanisms of quantitative traits that helps in the selection of suitable parents under a hot and dry climate. Combining ability analysis was used to get progenies with desirable traits under agro ecological zone of Thal. These analyses were applied to 21 (direct crosses) hexaploid spring bread wheat F₁ populations according to 7×7 diallel fashion biometrical approach under three heat stress regimes at Arid Zone Research Institute, Bhakkar, Pakistan during 2018-19 to 2020-21, i.e., TWS12464, TWS1335-1, TWS11510, TWS15105, TWS1578, TWS12245, Gold-16. Spring bread wheat is also known as spring wheat that is planted in spring and harvested in late summer. Results indicated that the mean squares of most traits proved highly significant due to the general combining ability (GCA) and specific combining ability (SCA). The variance ratios of GCA/SCA revealed all of the traits were predominantly under additive genetic control. TWS12464 was the best combiner with a maximum mean performance of all the traits in all temperature stresses followed by the parent namely Gold-16. Moreover, crosses TWS12464 × Gold-16 and TWS1335-1× TWS12464 were the best F1 hybrids. These crosses depicted good positive effects of SCA along with maximum mean performance for dry biomass per plant at anthesis, spikelets per spike, spike length, grain yield per plant in three test environments. These outperforming strains could be used to develop high-yielding temperature stress-resilient wheat cultivars to mitigate the grain yield gap in country terminal heat-prone ecological zone.

Temporal heat stress mitigation and physiological response in Abelmoschus esculentus L. by foliarly supplied salicylic acid

2023-09-12T08:20:47+05:00

Elevated global temperatures due to climate change have emerged as a significant concern for vegetable production. Heat stress drastically affects various physiological, developmental, and growth processes in horticultural crops. The temperature was enhanced gradually when the early sown plant was 50 days old (S₁), the second sown plant was 40 days old (S₂), and the third sown plant was 30 days old (S₃). Foliar applications of salicylic acid (1.5 mM) on the vegetative and physiological response of open-pollinated okra cultivar ‘Sabzpari’ plants subjected to heat-induced stress. The findings indicated that all sowing intervals significantly influenced plant vegetative and physiological attributes compared to control. Furthermore, S₁ plants exhibit more resilience to heat stress in comparison to S₂ and S₃ plants. In addition, the S₁ plant with foliar supplied 1.5 mM salicylic acid, exhibited a higher number of leaves, shoot length, root length, fresh weight, dry weight, chlorophyll contents, photosynthetic rate, stomatal conductance, water use efficiency, and lower transpiration rate under heat stress conditions. By applying SA, the dry biomass of the seedling increased 1.30 times as compared to the control. In S₁, dry biomass increased 1.33 times as compared to control. Notably, the treatment of 1.5 mM SA led to a significant increase of approximately 1.19 times as compared to the control, and among sowing intervals, S₁ showed 1.19 times increase. Nevertheless, the okra plants exhibited significant resilience to heat stress when salicylic acid was applied during the S₁ interval. Hence, the application of salicylic acid (1.5 mM) through foliar spraying, specifically at the S₁ interval, presents a practical strategy for mitigating the detrimental impacts of heat stress on the okra cultivar ‘Sabzpari’.

Evaluation of soil fertility status of fruit orchards of Gilgit district, Gilgit Baltistan

2023-09-12T08:02:39+05:00

The productivity of fruit trees orchards mainly relies on soil fertility and nutrient requirements. For best growth and production, essential nutrients are required optimally. To restore productivity soil characteristics and nutrient status of orchards must be determined. A multi locational orchards survey was conducted to assess the nutrient status (apple, almonds, walnut, fig, lokad, permission and stone fruits) of fruit orchards in district Gilgit, Pakistan. Samples were collected from the canopy area of the fruit trees at depth, viz, 0-20 cm using a stainless auger and analyzed for pH, EC, soil texture, organic matter, available phosphorus and potassium, AB-DTPA micronutrients. Results showed soil texture varied from sandy loam to silt loam. 56 % of samples were sandy loam with slightly neutral to alkaline pH. Non-saline soils having medium to high organic matter, Phosphorus levels varied from 0.57 to 39.7 mg kg^-1, and total nitrogen was inadequate in 60% of the soil samples, however adequate K was found due to K bearing minerals. Soil micronutrient (Cu, Fe, and Mn) except Zn was sufficient in all fruit’s orchards. 77 % of samples were low in Zn content where 4% of samples were in marginal range and 19% of samples were in the adequate range. Most of the fruit’s orchards were low in Zn and total nitrogen. The chemical soil conditions in fruit orchards are often poor, emphasizing that integrated nutrient management through fertilization regulation and soil property monitoring is essential for long-term fruit production in Gilgit district.

Berseem-Rhizobium symbiosis boosted growth and yield in the presence of rhizobacteria

2023-09-12T07:29:36+05:00

Legume-Rhizobium symbiotic relationships produced is beneficial and provides a natural mode of N₂-fixation via the mini nitrogen factories i.e., nodules. The species of Rhizobium has an extraordinary ability to fix nitrogen to plants species and resultantly less mineral nitrogen is required for crop growth. Filed study was designed on berseem to assess the symbiotic and rhizobacteria on berseem growth and yield under varied levels of nitrogen. The screening of isolates of symbionts and non-symbionts (04 of each) has been carried out for different biochemical functions. The bacterial isolates showed promising results for IAA equivalents, solubilization index, siderophore unit (quantitively & qualitatively) and other tests were done in field experiment at varied nitrogen levels i.e., 15 & 30 kg N ha^-1. Results revealed that bacterial inoculation either applied separately or in combined form demonstrated significant results at each N level in comparison to control. Results of yield contributing components suggested that co-inoculation produced higher berseem fodder & dry matter yield i.e., 76.7, 16.3 t ha^-1 at 30 kg N ha^-1 in comparison to 76.2, 15.7 t ha^-1 at 15 kg N ha^-1, respectively. Co-inoculation also improved the nodule no. and nodular mass i.e., 28.5 and 0.254 g plant^-1 as compared to the remaining inoculation levels at higher level of N. Co-inoculation (Br₄ & Pg₄) produced the maximum seed yield i.e., 368.7 kg ha^-1 than control i.e., 331.7 kg ha^-1. Higher N-P content was observed in seed and plant matter in different cuttings of berseem due to co-inoculation. The synergism between Rhizobium sp and rhizobacteria could be used after thorough screening and more valued approach as compared to separate application of microbes. Studies should be carried out to various legumes to accomplish beneficial effects of rhizobacteria along with symbionts to improve yield contributing factors and other quality indicators.