Search

Insufficient mobilization of pre-anthesis photosynthates from vegetative sources to reproductive sinks during achene growth and development plays a key role in reduced productivity of sunflower. Among different essential plant nutrients, a micronutrient boron (B) is known to have a prominent role in the mobilization of pre-anthesis reserves. A field experiment was carried out to investigate the role of soil applied boron in the mobilization and partitioning of pre-anthesis photoassimilates in early and late sown sunflower hybrid. Treatments were comprised of sowing dates (S) randomized in main plots and different rates of boron (B) randomized in sub plots. Treatments were S1= Normal sowing (Mid-February); S2= Late sowing (1st week of March) and B1= Control; B2= Water spray; B3= 1.5 kg B ha-1 at button stage; B4= 2 kg B ha-1 at button stage; B5= 2.5 kg B ha-1 at button stage; B6= 1.5 kg B ha-1 at ray floret stage; B7= 2 kg B ha-1 at ray floret stage; B8= 2.5 kg B ha-1at ray floret stage. Soil applied boron significantly improved the dry matter accumulation (fresh and dry weight of leaf, stem, head and whole plant) and mobilization of photosynthates, capitulum diameter, number of achenes per head, 1000-achene weight, achene and biological yield. Moreover, achene oil and protein contents also increased by the soil application of boron. Normal sowing date was more effective for mobilization of reserves. However, application of B (2-2.5 kg ha-1) mitigated the adverse effects of late sowing to a considerable extent. [ABSTRACT FROM AUTHOR]

A little is known about the brassica species response to different phosphorus (P) amendments and its effects on accumulation of P, proteins, oil and fatty acids in canola (Brassica napus L.) seeds. The two years field study was conducted to evaluate the yield and quality of canola hybrids (Hyola-401 and Hyola-43) in response to different P management strategies. The two canola hybrids were tested under different P application rates (@ 30 kg ha-1 or 60 kg ha-1) applied through broadcasting and side-drilling, alone and in combination with farmyard manure (FYM). Phosphorus applications have significant positive linear (p>0.05%) effects on yield and yield components in the both canola hybrids. The maximum seed yield (2749±6.96 kg ha-1; 2698±7.67 kg ha-1), oil contents (43.73±0.18%; 42.20±0.20%), protein contents (26.23±0.12%; 26.37±0.12%) and P accumulated in grains (0.52±0.01%; 0.45±0.02%) were recorded in Hyola-43 when fertilized @ 60 kg P ha-1 through side drilling along with FYM during 2004-05 and 2005-06, respectively. Hyola-43 appeared a good crop yielding canola hybrid as compared to Hyola-401. The high oleic and low linolenic acid provide good quality oil during frying process. Two folds increase was observed P accumulation in grain and this increase in endogenous grain P may have significant effects on next crop growth on soils having low inherent P. The study result suggests incorporating of FYM along with P fertilizer to overcome the issues of world inorganic P reserves utilization and for the sustainable higher quality canola production. [ABSTRACT FROM AUTHOR]

Water stress is a major constraint in crop production particularly in arid and semiarid regions of the world including Pakistan. Screening of maize germplasm at early stage is an effective tool for successful crop production in these areas. A pot experiment was conducted to screen seven maize hybrids namely 32F10, 32B33, 33H35, 3335, 34N43, 6142, 6525 at 80, 60 and 40% water holding capacities. A completely randomized design (CRD) with four replications was used. Results revealed that hybrid 34N43 recorded maximum emergence index, emergence energy, uniformity of emergence, final emergence percentage, shoot length, plant biomass and leaf area and maintained maximum water potential, osmotic potential, turgor potential and relative water contents whereas mean emergence time and time taken for 50% emergence was minimum for this hybrid under all three water holding capacities. While the performance of hybrid 32F10 was poor with respect to emergence, early growth and water relations under well watered conditions generally and under water stress particularly. Hybrid 32F10 proved to be the most sensitive to drought among the tested germplasm. Hence, it may be concluded that maize hybrid 34N43 would perform better under conditions of poor water supply as in Pakistan. [ABSTRACT FROM AUTHOR]

Iron availability in alkaline and calcareous soils is limited because of high pH and calcium carbonate contents. Various sources may have different solubilities within soil and may result in varying degrees of Fe availability. An incubation study was conducted to evaluate effectiveness of different sources of Fe to maintain water soluble Fe in different soils over passage of time. For this purpose, three different soils were incubated with various organic (Fe-EDDHA, Fe-DTPA, FYM) and inorganic (ferrous sulphate, vivianite) Fe sources for the period of four weeks. All amendments were adjusted to maintain 20 mg kg-1 of soil Fe except FYM. Iron sources showed significantly different behavior in maintaining soil Fe in different soils. The chelates of Fe proved very effective in maintaining soil solution Fe throughout the incubation period. Fe-EDDHA maintained 12 mg kg-1 with 56% recovery of total Fe added Followed by Fe-DTPA (with 30% recovery). Recovery of ferrous suphate was negligible on the first day of incubation. Vivianite which was prepared by mixing DAP fertilizer with FeSO4.7H2O also rapidly converted in to insoluble fractions on first contact to soils but maintained slightly more amount of soluble Fe as compared ferrous sulphate. [ABSTRACT FROM AUTHOR]