Explore the vast range of titles available.

Increasing global population and climate change uncertainties have compelled increased photosynthetic efficiency and yields to ensure food security over the coming decades. Potentially, genetic manipulation and minimization of carbon or energy losses can be ideal to boost photosynthetic efficiency or crop productivity. Despite significant efforts, limited success has been achieved. There is a need for thorough improvement in key photosynthetic limiting factors, such as stomatal conductance, mesophyll conductance, biochemical capacity combined with Rubisco, the Calvin–Benson cycle, thylakoid membrane electron transport, nonphotochemical quenching, and carbon metabolism or fixation pathways. In addition, the mechanistic basis for the enhancement in photosynthetic adaptation to environmental variables such as light intensity, temperature and elevated CO2 requires further investigation. This review sheds light on strategies to improve plant photosynthesis by targeting these intrinsic photosynthetic limitations and external environmental factors.

Indian squash ( Praecitrullus fistulosus ) crop faces heat and drought during its growth that is considered the most important abiotic stress in semi-arid areas. Seed priming with growth regulators enhances stress tolerance; hence, mitigates the adverse effects of unpredictable stresses due to adverse weather conditions. This two-year (2019 and 2020) study was conducted to infer the role of seed priming in improving heat tolerance of Indian squash (cultivar Sahavi) through improvement in physiological and antioxidant defense systems. Six treatments that included no priming (control), hydropriming, priming with indole acetic acid (IAA) at 100 mg L -1 , salicylic acid (SA) at 50 mg L -1 , ascorbic acid (AA) at 100 mg L -1 and thiourea at 500 mg L -1 each for 06 hours) were included in the study. Results revealed that priming with AA and SA significantly ( P ≤ 0.05) enhanced germination (39 and 47%), germination index (57 and 58%), plant height (23 and 22%), vine length (15 and 14%), number of fruits per plant (62%), fruit weight per plant (66 and 67%), economic yield (32%), photosynthesis rate (18 and 17%), protein content (10%), proline (23%), glycine betaine (3%), malondialdehyde content (11 and 10%) and catalase activity (24%) compared to control treatment. Furthermore, seed priming with AA and SA significantly ( P ≤ 0.05) shortened the mean germination time (25 and 28%) compared to the control. The results indicated that AA and SA had significant potential to mitigate adverse effects of heat stress in Indian squash. Findings from this study showed that seed priming with AA and SA promoted heat-stress tolerance and enhanced growth and productivity of Indian squash.

Field trials were conducted at eight different locations in Gujranwala and Sheikhupura districts during summer season, 2020 to determine the most profitable and economical planting method for PK-386 and Super Basmati cultivars of rice. Three planting methods viz. direct seeded rice (DSR), mechanical transplanting of rice (MTR) and conventional transplanting of rice (CTR) were compared at various locations. Data on yield-contributing traits and paddy yield were recorded. An Economic analysis was also carried out to determine the cost-effective planting method. Rice cultivars PK-386 and Super Basmati produced the highest number of tillers (410 and 350 m-2) under DSR, while the lowest number (276 m-2 and 253 m-2) from CTR, respectively. Number of grains per panicle and 1000-grain weight remained unaffected from planting methods whereas paddy yield was significantly influenced by various planting methods. The highest paddy yield of PK-386 and Super Basmati (5.59 t/ha and 4.34 t/ha) was recorded from DSR followed by MTR (4.82 t/ha and 3.92 t/ha), while the lowest paddy yield (4.50 t/ha and 3.80 t/ha) was observed from CTR. Economic analyses exhibited the highest net income (Rs.132308 and 302684 ha-1) from PK-386 and Super Basmati, respectively grown under DSR. Among all the three rice planting methods, DSR attained the highest paddy yield as well as net income therefore, it is advisable that farmers should adopt DSR technology for growing both varieties.

Weed infestation is a persistent problem for centuries and continues to be major yield reducing issue in modern agriculture. Chemical weed control through herbicides results in numerous ecological, environmental, and health-related issues. Moreover, numerous herbicides have evolved resistance against available herbicides. Plant extracts are regarded as an alternative to herbicides and a good weed management option. The use of plant extracts is environmentally safe and could solve the problem of herbicide resistance. Therefore, laboratory and wire house experiments were conducted to evaluate the phytotoxic potential of three Fabaceae species, i.e., Cassia occidentalis L. (Coffee senna), Sesbania sesban (L.) Merr. (Common sesban) and Melilotus alba Medik. (White sweetclover) against seed germination and seedling growth of some broadleaved weed species. Firstly, N-hexane and aqueous extracts of these species were assessed for their phytotoxic effect against lettuce ( Lactuca sativa L.). The extracts found more potent were further tested against germination and seedling growth of four broadleaved weed species, i.e., Parthenium hysterophorus L. (Santa-Maria), Trianthema portulacastrum L. (Pigweed), Melilotus indica L (Indian sweetclover). and Rumex dentatus L. (Toothed dock) in Petri dish and pot experiments. Aqueous extracts of all species were more toxic than their N-hexane forms for seed germination and seedling growth of lettuce; therefore, aqueous extracts were assessed for their phytotoxic potential against four broadleaved weed species. Aqueous extracts of all species proved phytotoxic against T . portulacastrum , P . hysterophorus , M . indica and R . dentatus and retarder their germination by 57, 90, 100 and 58%, respectively. Nevertheless, foliar spray of C . occidentalis extract was the most effective against T . portulacastrum as it reduced its dry biomass by 72%, while M . alba was effective against P . hysterophorus , R . dentatus and M . indica and reduced their dry biomass by 55, 68 and 81%, respectively. It is concluded that aqueous extracts of M . alba , S . sesban and C . occidentalis could be used to retard seed germination of T . portulacastrum , P . hysterophorus , M . indica and R . dentatus . Similarly, aqueous extracts of C . occidentalis can be used to suppress dry biomass of T . portulacastrum , and those of M . alba against P . hysterophorus , R . dentatus . However, use of these extracts needs their thorough testing under field conditions.

Oilseed crops require several micronutrients to support their physiological functions and reproductive phases. A deficiency of these nutrients can significantly reduce the yield and oil quality of oilseed crops. Soil application of micronutrients can reduce their deficiency and improve plant growth, yield, and oil quality. Oilseed rape (Brassica napus L.) is an important oilseed crop that produces oil with low levels of saturated fat and high levels of beneficial omega-3 fatty acids, which renders it a widely used cooking oil. However, the yield and oil quality of oilseed rape are significantly affected by the deficiency of boron (B) and zinc (Zn). This two-year field study determined the influence of sole and combined soil application of B and Zn on the physiological attributes of plants, seed and oil yields, and oil quality under semiarid climatic conditions. Nine different B and Z combinations, i.e., B0 + Zn0 (control), B0 + Zn8, B0 + Zn10, B1 + Zn0, B1 + Zn8, B1 + Zn10, B2 + Zn0, B2 + Zn8, and B2 + Zn10 (kg ha−1), were included in the study. Sole and combined application of B and Zn significantly altered physiological attributes, seed and oil yields, and oil quality. The highest values for plant height, number of siliques per plant, number of seeds per silique, 1000-seed weight, seed and oil yields, oil quality (higher stearic acid, palmitic acid, oleic acid, linoleic acid, linolenic acid, and lower erucic acid), and physiological traits (protein concentration, soluble sugar concentration, chlorophyll concentration, photosynthesis and transpiration rates, and stomatal conductance) were recorded with the combined application of 2 + 8 kg ha−1 B and Zn, respectively, during both years of this study. The lowest values of yield- and oil-quality-related traits and physiological attributes were recorded for the control treatment. A dose-dependent improvement was recorded in B and Zn contents in leaves, and the highest values were recorded with the combined soil application of 2 + 10 kg ha−1 B + Zn, respectively. It can be concluded that 2 + 8 kg ha−1 B + Zn should be applied to oilseed rape for higher seed and oil yields and better oil quality under semiarid climatic conditions.

Sawdust as a soilless growth substrate for plants is becoming popular in greenhouse production. However, fresh sawdust often requires time for decomposition before it is ready for use as a growth substrate. We studied whether amendments of banana peels (as a source of potassium), eggshells (as a source of calcium), and urea (as a source of nitrogen) in non-composted fresh chinaberry (Melia azedarach) sawdust could enhance its potential as a growth medium. In two pot experiments, the growth of okra (Abelmoschus esculentus (L.) Moench) was evaluated using mixtures of non-composted M. azedarach sawdust. The treatments were: (T1) 100% soil (control) (vol/vol); (T2) 100% M. azedarach sawdust (vol/vol); (T3) 80% M. azedarach sawdust +20% banana peel (vol/vol); (T4) 60% M. azedarach sawdust +20% banana peel +20% eggshell (vol/vol); and (T5) 60% M. azedarach sawdust +20% banana peel +20% eggshell (vol/vol) +91 kg N ha−1 (urea). There was no significant difference between the treatments regarding seed germination and okra emergence, but leaf area, chlorophyll content index, plant biomass, number of pods per plant−1, fresh pods, and dry weight were significantly lower in pots with fresh sawdust mixtures. Organic amendments of banana peels and eggshells improved the sawdust substrate. Adding a further 91 kg N hectare−1 improved the growth but was insufficient to produce the same yield of okra as in non-fertilized sandy clay loam soil. We cannot exclude that non-composted M. azedarach sawdust may be a potential growth substrate for okra, but the amendments added were not enough to obtain the same yields as when okra was grown in soil.

A pot experiment was conducted to investigate the role of thiourea exogenous application (0 mg/L and 100 mg/L) on the morphological, physiological, and yield traits of two varieties of tomato (Naqeeb and Nadir) under different salt stress treatments (0, 60, and 120 mM) in completely randomized design (CRD). The imposition of salinity by rooting medium showed that salt stress reduced plant height by 20%, fresh shoot weight by 50%, dry shoot weight by 78%, fresh root weight by 43%, dry root weight by 84%, root length by 34%, shoot length by 32%, shoot K+ by 47%, Ca2+ by 70%, chlorophyll a by 30%, chlorophyll b by 67%, and the number of seeds per berry by 53%, while shoot Na+ ions were increased by 90% in comparison to those grown with control treatment. However, the exogenous application of thiourea significantly enhanced dry root weight by 25% and the number of seeds per berry by 20% in comparison to untreated plants with thiourea when grown under salt stress. Salt stress resulted in a reduction in the number of berries, weight per berry, number of seeds per berry, and seed weight in both varieties, while thiourea foliar application increased these yield parameters. On the other hand, the Nadir variety surpassed Naqeeb in plant height (+13%), root length (+31%) and shoot length (+11%), fresh shoot weight (+42%) and dry shoot weight (+11%), fresh root weight (+29%), dry root weight (+25%), area of leaf (+26%), chlorophyll a (+32%), and chlorophyll b (+24%). In conclusion, the exogenous application of thiourea can be used to mitigate salt stress in tomato plants since it can improve the growth, physiological, and yield traits of this strategic crop.

Red sprangletop (Leptochloa chinensis L.) is a problematic weed of aerobic rice (Oryza sativa L.) that greatly reduces in yield. The laboratory studies were undertaken to confirm allelopathicity of its plant leachates and soil-decomposition plant residues towards emergence and seedling growth of rice. In first experiment, aqueous extracts from various plant parts of red sprangletop (stem, root, leaves, flower and entire plant) at their 5% (w/v) concentration were applied to germinating rice seeds. In second experiment, soil-decomposed red sprangletop plant residues of variable concentrations (2, 4 and 6% w/w) were used as germination media for rice. Among plant parts, red sprangletop leaves showed maximum allelopathic effect by fully inhibiting the germination of rice while its stem could be positioned at second situation as it caused 60, 73, 84.13 and 86 % reductions in germination percentage, germination index, seedling length and seedling dry biomass of rice as compared with control, respectively. This treatment also resulted in maximum delays in mean germination time (up to 4.80 days) and days taken to 50% germination (up to 4.40 days) of rice. The highest concentrated (6%) soil-decomposed plant residue of red sprangletop significantly diminished the germination percentage, germination index, seedling length and seedling vigor index that were 35.13, 23.26 and 41.61% lower than control. It very well may be presumed that liquid concentrates of leave and stem soil-decomposed plant residues of 6% concentration had different kind of allelochemicals that inhibited the germination, seedling growth and development of rice.

Appropriate sowing time is an important aspect that can affect the gowth and yield of any crop. So, a research trial was planned at Research Area, College of Agriculture, University of Sargodha, Pakistan to investigate the impect of different sowing dates on growth and yield on mungbean cultivars. The research trial was arranged out in randomized complete block design (RCBD) under split plot arrangement followed by 3 replicas. In this study four different sowing dates (1st March, 15th March, 29th March and 12th April and two cultivars (AZRI-2006 and NM-92) were used. Data regarding leaf area index, leaf area duration, plant height (cm), number of pod bearing branches per plant, number of grains per pod,1000-grain weight (g), grain yield (kg ha-1), biological yield (kg ha-1) and harvest index (%) of mungbean were recorded by using standrd procedure. Results of experiment revealed that sowing date of 1st march and varity AZRI-2006 result in maximum leaf area index (3.43), leaf area duration (24.14), plant height (74.067cm), number of pod bearing branches per plant (60.96), number of grains per pod (11.30), grain yield (715.11 kg ha-1), biological yield (7773.3 kg ha-1) and harvest index (9.6167%) while sowing date 12th april and Varity AZRI-2006 produce maximum 1000-grain weight (66.67 g). On the bases of result of this study it was concluded that sowing date of 1st march and varity AZRI-2006 play important role in aching maximum yield of mungbean.

Blessed milkthistle is considered to be a noxious weed in irrigated and rainfed areas of Pakistan due to its strong allelopathic effects on food crops. For sustainable wheat production, it is necessary to know the critical time for weed removal (CTWR) for blessed milkthistle to allow wheat growers to get maximum benefit from control of this weed. A field study was conducted in 2014 and 2015 at the College of Agriculture, University of Sargodha, Pakistan, to investigate the CTWR of blessed milkthistle in wheat. The field experiments were designed with seven treatments; weed free (control); 2, 3, 4, 5, and 6 wk after emergence (WAE); and weedy check. At 6 WAE, a significant reduction was noted in plant height (8% and 17%), number of productive tillers per square meter (16% and 16%), spike length (23% and 54%), grains per spike (13% and 34%), 1,000-grain weight (14% and 37%), grain yield (20% and 21%), and biological yield (24% and 50%) compared with control (weed-free plots) during 2014 and 2015, respectively. The logistic model supports the field study results and suggests that blessed milkthistle's CTWR for wheat is 1 to 5 WAE based on acceptable yield losses of 5% to 15% during both years. The experimental results and logistic model indicate that blessed milkthistle should be controlled within 1 to 5 WAE to get better wheat crop harvests without compromising farmers' profits. To our knowledge, this is the first study ever in Pakistan regarding the CTWR in terms of WAE of blessed milkthistle and could help other scientists create weed control strategies for other areas of the country. Nomenclature: Blessed milkthistle, Silybum marianum (L.) Gaertn.; wheat, Triticum aestivum L.