Allelopathic Potential of Soliva sessilis Ruiz & Pav. on Wheat

Soliva sessilis (Burweed) is a winter annual weed found in wheat crop of Pakistan. It is thought to have an allelopathic effect on wheat crop. In this regard, an experiment was conducted in 2019 in the department of Weed Science and Botany at the University of Agriculture Peshawar, to assess the allelopathic potential of S. sessilis on various wheat varieties grown in Peshawar, Pakistan. Physiologically matured roots and leaves of S. sessilis were dried, ground and stored. Three common wheat varieties were selected for the research including Atta Habib, Pirsabaq-15, and Shahkar-13. The treatments of the experiment comprised of the aqueous extracts of the roots and leaves of S. sessilis, hot water extracts, methanol extracts, litter, and mulches. A mass of 5?g of S. sessilis was taken for the different extracts for 24?h, however, the methanol extract was kept for 48?h. The effect of the treatments was highly significant on wheat seed germination, radicle length, plumule length, fresh biomass as well as dry biomasses of the three tested wheat varieties. The variety Atta Habib was discovered as the most susceptible variety to the treatments of aqueous extracts, hot water extracts, and leaves’ litter. In contrary, the variety Pirsabaq-15 exhibited a remarkable increase in the various data collection parameters. The leaves of S. sessilis were observed more toxic as compared to the roots. The mulch of S. sessilis indicated stimulatory effect on the wheat varieties. For the interaction effect between treatments and varieties, the leaves and roots aqueous extract and their litter showed inhibitory effect. In conclusion, the leaves and roots of S. sessilis are potentiality allelopathic to wheat crop plants and further study is needed to assess the types of these allelochemicals present in the leaves and roots of the weed.

     

Agroforestry Systems as Alternative Land-Use Options in the Arid Zone of Thal,Pakistan

Agroforestry offers unique opportunities for increasing biodiversity, preventing land degradation, and alleviating poverty, particularly in developing countries, but factors explaining the adoption by farmers are not well understood. A survey of 524 farm households was conducted in Bhakkar district of Punjab, Pakistan to study factors that determine the adoption of agroforestry on the sand dunes in the resource-deficient region of Thal. Two types of agroforestry systems were studied: intercropping and border cropping (also known as boundary or perimeter planting). Both agroforestry systems included irrigated cultivation of the timber trees Eucalyptus camaldulensis (local name: sufeda) and Tamarix aphylla (local name: sars) with wheat, chickpeas (Cicer arietinum) (local name: chana) or cluster beans (Cyamous tetragocalobe) (local name: guars). The majority of the farmers was in favour of intercropping and border cropping. Most farmers reported the protection of nearby crops from dust storms as the most important positive perception about both agroforestry systems. Age, education, and farm to market distance were significant determinants of agroforestry adoption. Older and less-educated farmers, with farms closer to markets were less likely to adopt tree planting or border cropping in Thal. In general, the agroforestry systems examined were more likely to be adopted by farmers who can wait 3–4 years for harvesting crop outputs, but not by poorer farmers who are totally dependent on subsistence agriculture and cannot afford the high initial cost of agroforestry establishment, nor can they wait for crop output for extended periods. Furthermore, the adoption of both agroforestry systems was more likely in remote marginal areas than in areas close to markets. To increase agroforestry adoption rates, government policies should strengthen farmers’ knowledge of every stage of agroforestry through extension services, focusing particularly among the prime prospects, i.e. farmers who will be most likely to adopt agroforestry. Once the prime prospects have adopted it, the older, less-educated, and poor farmers of the rural population can be also focused on to motivate adoption.     

Significance of sulfur in heat stressed cluster bean (Cymopsis tetragonoloba L. Taub) genotypes: responses of growth,sugar and antioxidative metabolism

A sand culture experiment was carried out to study the effects of sulfur deprivation on heat stress tolerance of two cluster bean (Cymopsis tetragonoloba L. Taub) cultivars (GC-1 and Pusa Nau Bahar (PNB)). Three weeks old sulfur-starved and sulfur-supplemented plants were subjected to heat stress (45°C/35°C) treatment for 24 h. Total dry weight, chlorophyll content, Chlorophyll a:b ratio, electrolyte leakage, malondialdehyde (MDA) accumulation, H₂O₂ content, sugar, glucose-6-phosphate (G-6-P), fructose-6-phosphate (F-6-P), ascorbate and glutathione concentrations and antioxidant enzyme activity (superoxide dismutase (SOD) and catalase (CAT)) were monitored, at the end of the heat stress treatment. Heat stress enhanced and sulfur starvation depleted the contents of sugar metabolites, but the accumulation of sugar, G-6-P and F-6-P were not related with heat stress tolerance. Antioxidant enzyme activities of SOD and CAT were influenced significantly more by sulfur starvation than heat stress. The results showed that under heat stress, the addition of sulfur helps to mitigate the oxidative damage in both the cultivars. However, GC-1 was more heat tolerant as it was characterized by significantly higher total dry weight, chlorophyll content, ascorbate and glutathione content and lower H₂O₂, MDA, electrolyte leakage than PNB.