No abstract

The production of safer and healthy foods using sustainable and environmentally friendly agricultural practices plays a vital role in determining their market value and nutritional benefits. In this context, due to continuously changing environmental attributes, the risk factors related to sustainable agriculture and product safety are being increasingly investigated (Arshad and Shafqat, 2012). In recent years, through utilizing effective strategies such as valid farm management practices and mechanized agriculture, efforts have been made to enhance the growth and productivity of various crops without compromising food quality standards (Chaudhry et al., 2006). Plant growth regulators (PGRs), due to their multiple growth and physiological functions, are gaining recognition as an emerging agricultural practice. However, some risk factors associated with the applications of PGRs have also been observed in certain agricultural practices in the form of volatilization, chemical degradation, leaching, oxidation, etc. Therefore, in order to gain increased efficiency in targeted crops, the effective use of appropriate doses of PGRs is recommended (Aslam et al., 2013).Spinach (Spinacia oleracea L.), a member of the family Amaranthaceae, and, like other leafy green vegetables, is a valuable source of essential minerals and important bioactives required for proper growth and bodily functioning. In Pakistan, this leafy green vegetable is locally known as "palak". It is now widely recognized that dietary fiber and phytochemicals such as flavonoids, vitamins, carotenoids, phenolic acids, and phytosterols, which are inherent formulations of spinach and other leafy green vegetables, are associated with lowering the risk of certain diseases such as cataracts, diabetes, high blood pressure, obesity, coronary heart disorders, and certain cancers (Djousse et al., 2004;Hung et al., 2004). Such high-value compounds have been reported to exhibit multiple biological effects, including cytotoxic, antimutagenic, antioxidant, antiviral, and antifungal activities (Hounsome et al., 2008).

Salinity is a serious problem that limits crop growth and yield. The present study used plotting to evaluate 25 tomato (Solanum lycopersicum L.) accessions for various morpho-physiological parameters at the seedling stage and identify significantly salt-tolerant tomato lines at three different salinity levels. The pot experiment had a completely randomized design with three replicates in a factorial arrangement under greenhouse conditions. Tomato plants were exposed to 0 (control), 8, and 12 dS m-1 as NaCl stress at the seedling stage. The morpho-physiological traits, such as root and shoot length, root/shoot ratio, number of leaves, fresh and dry shoot weight, fresh and dry root weight, leaf area, Na + and K + concentrations, K + /Na + ratio, and tolerance index, were recorded to examine salt tolerance. According to principal component analysis (PCA), there were six principal components (PCs) with Eigen values > 1 and 77.2% of total cumulative variability. The PC1 (24.3%) revealed the highest variability followed by PC2 (16.2%).

The aim of this study was to reduce the breakdown of hybrid vigour by crossing maize × teosinte subspecies through induced tetraploidy and to improve the biomass and reproductive fertility of the induced tetraploids. To achieve this, seeds of maize breeding lines selected from an open‐pollinated population ‘Sargodha‐2002’ and a maize × teosinte cross were germinated in colchicine solution (0·25, 0·5 or 1·0%) until they had a thick radical and protruded plumule. Colchicine at 0·5% induced the highest number of tetraploids with the lowest number of chimeric plants. The induced tetraploids of maize and maize × teosinte crosses showed a significant (P ≤ 0·05) increase in leaf area (5 and 14%), total soluble solids (20 and 18%), leaf oil percentage (42 and 12%) and leaf crude protein contents (10 and 14%) in leaves relative to the diploid subspecies. Moreover, induced tetraploidy also arrested hybrid vigour by slowing down the decay of heterosis in progenies (4x) for plant height, leaf biomass and leaf oil percentage. Induced maize × teosinte hybrid tetraploids selected for frequent bivalent chromosome pairing resulted in higher seed setting cob−1 (increased 58%), pollen fertility (increased 59%) and seed setting percentage (increased 100%) than the quadrivalent variant.