Aphid Dynamics in Relation to Meteorological Factors and Various Management Practices in Bread WheatThe infestation of aphids in wheat is becoming a serious problem nowadays and it might become a threat to the future wheat crop in Pakistan. With this problem in mind we did a study pertaining to aphid dynamics in relation to meteorological factors and various management practices in bread wheat. The study was carried out at the Wheat Research Institute, Faisalabad, Pakistan. The aim of this study was to investigate how meteorological factors play a role in the fluctuating aphid population and how different management practices could be effective in combating aphids. The results revealed that a peak aphid population was recorded during the beginning of the third week of March for both of the study year periods of 2007-2008 and 2008-2009. Aphid density was positively associated with maximum as well as minimum temperature while it showed a negative correlation with relative humidity. However aphid population was positively but not significantly affected by rainfall. Early sowing on 1st November produced the least aphid infestation hence early sowing was encouraged as a cultural practice for keeping aphids below damaging levels. The recently developed wheat varieties like: SHAFAQ-06, SEHER-06, FSD-08 and LASANI-08, revealed aphid resistance and performed better against aphids. On the other hand the genotypes V-05003, BARS-09 and 0BT006, revealed maximum vulnerability to aphids. Number of aphids per tiller was positive correlated with loss in grain yield. Application of insecticide significantly controlled the aphid population which suggested that a combination of host plant resistance with chemical control could restrain the aphid infestation in wheat.

The major wheat-producing countries have heterogeneous and fragile agro climatic surroundings but frequently restraining wheat yield and quality losses are predominant under heat and drought prone agriculture exclusively when both stresses occur in blend, which looms the food security globally. However, many suggested examples are available in these countries for the mitigation of these two stresses by using different conventional and modern improvement and agronomic approaches. In addition to these approaches, morphological, physiological, anatomical, biochemical, phenological, and physiochemical vicissitudes, which trigged during these stresses, have also been elucidated. There complete deliberation in combination for wheat improvement is still a contest, but a win-win option is a holistic attitude in future.

Increasing human population places pressure on agriculture. To feed this population, two time increase in the current wheat production is needed. Today agriculture is becoming input intensive with more reliance on synthetic fertilizers and agrochemicals to fulfil the feed demand of the growing numbers. Use of synthetic fertilizer since last few years is impacting the soil quality. In this scenario, the use of beneficial endophytic microbes is an attractive strategy to overcome the use of synthetic products. To investigate the effect of consortium application of endophytic bacteria and fungus on plant growth, grain yield moisture status, a pot experiment was conducted in different wheat lines. It comprised four treatments like control, application of bacterial strain Bacillus sp. MN54, fungal strain Trichoderma sp. MN6, and their consortium (Bacillus sp. MN54 + Trichoderma sp. MN6). The effect of consortium application was more prominent and significantly different from the sole application of bacteria and fungus. The results showed that with a consortium application of endophytic bacteria and fungus, there was 28.6, 4.3, -6.3 and -3.7% increases in flag leaf area, chlorophyll content, relative membrane permeability and water content respectively. Consortia of endophytic microbes also resulted in the yield enhancement through the betterment of various yield attributes like number of spikelet's, grains per spike and grain yield per plant (32.2, 25.8 and 30.8%, respectively). So, consortia of endophytic microbes can greatly promote the progress of plants in dry land agriculture and increase the yield in an environmentally sustainable way.

Soil Microbiologists have been concentrating on manipulation of rhizosphere microbes in cereals, but many researchers have reported that rhizobia can act as plant growth promoting rhizobacteria (PGPR). Rhizobium species impacted the crop ontogeny by root / endophytic colonization, producing phytohormones, efficient nutrient use and nutrient solubilization / mineralization. Field studies were performed at Soil Bacteriology Section and Soil Chemistry Section, Faisalabad to assess the comparative potential of Rhizobium species for promoting the growth, yield of wheat and rice. Auxin biosynthesis potential of isolates of Rhizobium species (mung (Vigna radiata), berseem (Trifolium alexandrinum), chickpea (Cicer arietinum), lentil (Lens culinaris) and peanut (Arachis hypogaea)) was determined and isolates of each species having higher values were used for field experiments. Assay for root / shoot elongation, root colonization in plates were carried out under controlled conditions. The rhizosphere soil of wheat and rice were assayed for the Indole Acedic Acid (IAA) content 15 and 30 days after germination / transplanting, respectively. Results revealed that significant increase was observed in the yield parameters of wheat and rice. Highest wheat grains were produced i.e., 4917 kg ha-1 with Rhizobium sp of mungbean (Mb3) followed by 4823 with Rhizobium sp of berseem (Br3) than control i.e., 4500 kg ha-1. Similarly, the maximum paddy yield i.e., 4667 kg ha-1 with Rhizobium sp of mungbean (Mb3) followed by 4625 Rhizobium sp of berseem (Br3) inoculation was obtained as compared to control i.e., 4208 kg ha-1. Other physical parameters of wheat and rice also showed positive response to inoculation and have elevated levels of IAA in the rhizosphere of inoculated treatments. Results clearly demonstrated that Rhizobium species increased the yield of rice and wheat.

No abstract