Abdul Rehman Khan

The effect of cultivar, sowing date and transplant location in field on bolting of Welsh onion ( Allium fistulosum L.)

BackgroundBolting reduces the quality and commercial yield of Welsh onion (Allium fistulosum L.) in production. However, seed production is directly dependent on flower induction and bolting. The Welsh onion belongs to the green plant vernalisation type, specific seedling characteristics and sufficient accumulated time at low temperature are indispensible for the completion of its vernalisation process. Only if these conditions for vernalisation are fulfilled, the plants will bolt in the following year. The present investigation evaluated the effects of cultivar, sowing date and transplant location in field on the bolting of Welsh onion at the Horticultural Farm of the College of Horticulture, Northwest A&F University, Yangling, Shannxi Province, China in two succeeding production years: 2010–2011 and 2011–2012. A strip split plot layout within a randomised complete block design with three replications was used.ResultsThe results revealed that all three factors (cultivar, sowing date and transplant location) and their interaction had significant effects on the initiation and final rate of bolting observed by 30 April. The earliest bolting date (14 February, 2011 and 15 February, 2012) and the highest bolting rate (100% in 2011 and 62% in 2012) occurred when the JinGuan cultivar was sown on 20 August and transplanted in a plastic tunnel, whereas the latest date and lowest rate (no bolting observed until 30 April) of bolting occurred when the XiaHei cultivar was sown on 29 September and transplanted in an open field.ConclusionsThese results suggest that we can control bolting in Welsh onion production by choosing an appropriate cultivar, sowing date and transplant location. Choosing a late bolting cultivar, such as cultivar XiaHei, sowing around October, and transplanting in the open field can significantly delay bolting, while a sowing date in late August should be selected for seed production, and the seedlings should be transplanted in a plastic tunnel to accelerate development of the flower buds.

Comparative Analysis of Putative Orthologues of Mitochondrial Import Motor Subunit: Pam18 and Pam16 in Plants

Pam18/Tim14 and Pam16/Tim16, highly conserved proteins among eukaryotes, are two essential subunits of protein import motors localized in the inner mitochondrial membrane. The heterodimer formed by Pam18 and Pam16 via their J-type domains serves a regulatory function in protein translocation. Here, we report that thirty-one Pam18 and twenty-six Pam16 putative orthologues in twelve plant species were identified and analyzed through bioinformatics strategy. Results data revealed that Pam18 and Pam16 were also highly conserved among plants including their J-type domains within the hydrophilic region. Key amino acid residues and an HPD motif of Pam18 were identical among the orthologues except OsPam18L5. N-myristoylation sites of Pam18 and casein kinase II phosphorylation sites of Pam 16 were more abundant, which might be important functional sites. Some Pam18 and Pam16 proteins contained a transmembrane region at the N-terminal region. Sub-cellular prediction results indicated that many orthologues localized at mitochondria. Gene expression analyses revealed that Pam18 and Pam16 in Arabidopsis might play roles in senescence and abiotic stress responses. Our detailed study provides a better understanding of Pam18 and Pam16 in plant kingdom.

Pepper-garlic intercropping system improves soil biology and nutrient status in plastic tunnel.

A two year (2009-2011) experiment was conducted to investigate effect of pepper-garlic intercropping system on soil biology and nutrient profile in plastic tunnel to overcome continuous monocropping obstacles. During first year’s trial, garlic cloves of four cultivars (G026, G025, and G087 for the harvest of bulbs) were intercropped between two rows of pepper seedlings (cv. Golden Pepper) on each bed. Similarly, garlic bulb (cv G064 for the harvest of green seedlings) was sandwiched between two rows of pepper seedlings. During 2 nd year, the pepper crop was transplanted on the same beds already having garlic in the field of previous crop, following the same geometry. Sole pepper was grown as control. Both crops received uniform fertilization and irrigation as per requirements of pepper. Results revealed that concentration of soil bacteria and actinomycetes was higher respectively after one month of garlic intercropping during both the years of study as compared to the sole pepper; however, fungal population exhibited a diminishing trend. Soil protective enzyme activity (invertase, urease, and alkaline phosphatase) also showed dynamic changes after the intercropping of garlic. The principal soil nutrients (NPK) attained higher levels in pepper-garlic co-growth treatments as compared to the sole pepper The intercropping with green garlic (cv. G064) resulted highest nutrient levels suggesting that the effect might be cultivar specific. It was concluded that the intercropping of pepper with garlic enhances the soil fertility by changing nutrient levels, enzymatic activity and the soil microbial population. Overall, the pepper-garlic intercropping model provides a cost effective and eco-friendly organic farming system for vegetable growers.

Effects of Temperature during Seedling Stage on Growth and Nutrient Absorbance of Gerbera jamesonii Growing in Organic Substrate

The effects of different temperature treatments during the seedling stage on growth and nutrient absorbance of Gerbera jamesonii cv ‘Sunshine Coast’ growing in the organic substrate were investigated. The temperature treatments were conducted in growth chamber where the day/night temperature were set to 15/10, 20/15, 25/20, and 30/25°C individually. The results showed that the fresh and dry weight of aboveground part and that of roots, average number of leaves and lateral roots were greater at 30/25°C than other treatments. The highest level of macro elements nitrogen (N), phosphorus (P), and potassium (K) in the leaf samples were also detected at 25/20°C and 30/25°C. However, there was no significant influence of different temperatures on zinc (Zn) levels in leaves. In general, the day temperature 25∼30°C and night temperature 20∼25°C are thought to be the better temperature condition for gerbera growth as well as the nutrient uptake and accumulation in the plants during the seedling stage.