Resistance to foliage feeding aphid in wheat

Experimental trials were conducted at Integrated Pest Management Programme, National Agriculture Research Centre Islamabad, to evaluate the resistance of host plants (cereals) against Rhopalosiphum padi (L.). For evaluation of susceptibility, twenty varieties/-advanced lines of National Uniform Wheat Yield Trails (NUWYT) Normal (N) of year 2004-2005 were used. In seedling bulk tests varieties/advanced lines were grouped into three categories resistant, moderately resistant and susceptible. Data from seedling bulk tests showed that DN-47 and PR 87 lines of wheat were resistant to aphid as compared to the other varieties/-advanced lines. In antixenosis tests varieties/-advanced lines were grouped into three categories, least preferred, moderately preferred, highly preferred. Lines V-01180, DN-47 and PR-84 were least preferred, sixteen varieties/-advanced lines were moderately preferred and only one variety V-9021 was found to be highly preferred.     

Physico-chemical behaviour of the fish lipid from Lepidocephalus guntea (Hamilton) and variation of lipid profile with size

The fish lipid was extracted from the body muscle (edible portion) of fresh Lepidocephalus guntea (Ham.) fish and the lipid content of the fish in size-1 (below 8.5 cm), size-2 (8.5-9.5 cm) and size-3 (above 9.5 cm) were found to be 2.515, 3.013 and 3.455%, respectively. The specific gravity and refractive index of the lipid were found to be 0.93 at 30 degrees C and 1.467 at 31.5 degrees C, respectively. The saponification value, saponification equivalent, iodine value, peroxide value and acetyl value of the lipid were found to be 220.325, 254.624, 96.05, 1.993 and 11.32, respectively. The acid value, percentage of free fatty acid as oleic and unsaponifiable matter present in the lipid were found to be 2.005, 1.008 and 0.593, respectively. The fatty acid composition of the lipid was determined qualitatively and quantitatively by TLC and GLC. The analysis revealed that the fatty acid composition of the lipid lies between C14 to C20. The fish lipid of Lepidocephalus guntea (Ham.) was found to contain (average value) myristic acid (3.17%), palmitoleic acid (7.45%), palmitic acid (29.16%), linolenic acid (7.13%), linoleic acid (5.57%), oleic acid (22.93%), stearic acid (17.42%), arachidonic acid (7.17%) and arachidic acid in trace amount.     

Water relations and drought-induced embolism in olive (Olea europaea) varieties 'Meski' and 'Chemlali' during severe drought

We examined the effects of drought on the water relations, osmotic adjustment and xylem vulnerability to embolism of olive (Olea europaea L.) varieties, 'Meski' and 'Chemlali'. Two-year-old self-rooted cuttings growing in sand-filled pots in a greenhouse were subjected to water stress by withholding water for 60 days. Water relations and gas exchange measurements showed that 'Chemlali' was more drought resistant than 'Meski' and had a greater capacity for osmotic adjustment through solute accumulation. However, when water stress was acute, the effect of osmoregulation on leaf cell turgor was largely counteracted by xylem cavitation. Cavitation vulnerability curves showed that both varieties were highly resistant to embolism formation. The xylem water potential inducing 50% loss of stem conductivity approached -7 MPa in 'Meski' and only slightly less in 'Chemlali'. Although the difference between varieties in susceptibility to xylem embolism was small, it appears to account in large part for the difference between them in the ability to tolerate severe drought.     

Use of Lignocellulolytic Microbial Consortium and pH Amendment on Composting Efficacy of Rice Straw

ABSTRACT

The present study was conducted at the Composting Unit, Universiti Putra Malaysia to determine the physico-chemical changes, microbial dynamics, and enzyme activities during microbial composting of rice straw at different pH conditions. Different treatments comprising of composting substrates (A), substrates with microbial consortium (B), substrates, microbial consortium, and acetic acid (C), substrates, microbial consortium, and sodium hydroxide (D) were used to enhance the composting process of rice straw. In inoculated treatments, the temperature increased rapidly to higher than 50°C by day 5 and remained above 40°C up to day 17, while in the control the temperature increased slowly and peaked (46°C) at day 9 and remained above 40°C until day 23. The results showed that biodegradation was at its maximum in microbial-infused treatments within 14–21 days as indicated by profiles of pH, reduction of C/N ratio, lignocellulolytic (lignin peroxidase, endoglucanase, and exoglucanase) enzyme activities, and lignocellulose bioconversion. After day 21, the C/N ratio of microbial-infused treatment without any pH adjustment (B) was reduced to 17.5 from an initial value of 29.2 suggesting that there were no additive effects of pH adjustment during the microbial composting of rice straw.     

Interactive effect of shade and PEG-induced osmotic stress on physiological responses of soybean seedlings

Intensively farmed crops used to experience numerous environmental stresses. Among these, shade and drought significantly influence the morpho-physiological and biochemical attributes of plants. However, the interactive effect of shade and drought on the growth and development of soybean under dense cropping systems has not been reported yet. This study investigated the interactive effect of PEG-induced osmotic stress and shade on soybean seedlings. The soybean cultivar viz., C-103 was subjected to PEG-induced osmotic stress from polyethylene glycol 6000(PEG-6000) under shading and non-shading conditions. PEG-induced osmotic stress significantly reduced the relative water contents, morphological parameters, carbohydrates and chlorophyll contents under both light environments. A significant increase was observed in osmoprotectants, reactive oxygen species and antioxidant enzymes in soybean seedlings. Henceforth, the findings revealed that, seedlings grown under non-shading conditions produced more malondialdehyde and hydrogen peroxide contents as compared to the shade-treated plants when subjected to PEG-induced osmotic stress. Likewise, the shaded plants accumulated more sugars and proline than non-shaded ones under drought stress. Moreover, it was found that nonshaded grown plants were more sensitive to PEG-induced osmotic stress than those exposed to shading conditions, which suggested that shade could boost the protective mechanisms against osmotic stress or at least would not exaggerate the adverse effects of PEG-induced osmotic stress in soybean seedlings.     

Resistance profiles of Botrytis cinerea populations to several fungicide classes on greenhouse tomato and strawberry in Lebanon

Tomato and strawberry are the most important protected crops in Lebanon and are seriously affected by grey mould disease, caused by Botrytis cinerea. In the present study, the fungicide sensitivity assays revealed medium to high frequencies of B. cinerea isolates resistant to benzimidazoles, dicarboximides, and anilinopyrimidines on tomato and strawberry. Fludioxonil- and boscalid-resistant mutants were uncommonly found at generally low frequency on both crops. Resistance to fenhexamid was detected in only one site on tomato but in most sites on strawberry with high frequencies, and the occurrence of resistance to QoI fungicides was ascertained on both crops. The majority of the tested isolates (>90%) exhibited multiple fungicide resistance, and isolates resistant to the seven antibotrydial fungicide classes were detected on strawberry in three locations. A high level of resistance was shown by B. cinerea mutants resistant to boscalid, fenhexamid, and QoI fungicides, while two levels of moderate and high resistance to anilinopyrimidines were identified. Genetic analysis revealed point mutations in the target genes commonly associated with resistance in B. cinerea isolates, with all mutants resistant to dicarboximides, fenhexamid, boscalid, and QoI fungicides carrying single-nucleotide polymorphims in BcOS1 (I365S/N, Q369P, and N373S), Erg27 (F412V/I), SdhB (H272R/Y), and cytb (G143A) genes, respectively. The general incorrect use of fungicides has caused the development and spread of fungicide resistance as a widespread phenomenon on protected tomato and strawberry in Lebanon. The implementation of appropriate antiresistance strategies is highly recommended.     

Annually twice induced spawnings provide multiple benefits: Experimental evidence from an Indian major carp (Catla catla,Hamilton 1822)

Multiple spawnings are special reproductive tactics that many fish evolved to obtain different types of direct and/or indirect spawning benefits. This has led to two pertinent questions: (a) what types of benefit does a commercially important fish provide during multiple induced spawnings annually? and (b) is there any trade‐off between traits during these spawnings? To address these questions, the present study was carried out with two separate experiments during two spawning events of an Indian major carp (Catla catla) to assess: (a) male's spawning performances and (b) female's spawning performances. The male's spawning data revealed that they produced significantly higher amount of milt and hatchlings during the first spawning, while they significantly reduced hatchling deformation rate, enhanced offspring survival rate and enlarged offspring body size during the second spawning. The female's spawning information unveiled no significant differences in total egg weight, hatching rate and hatchling deformation rate between the first and second spawning. However, females had significantly higher offspring survival rate during the first spawning and enhanced offspring body size during the second spawning. Interestingly, the analysis of trait associations revealed that males allocated energy with a trade‐off between milt weight and offspring survival rate, whereas females showed a trade‐off between hatching rate and offspring survival rate. Thus, the study provides some important information for carp breeders and associated stakeholders to know which spawning season is preferable for the higher production of eggs, milt and good quality larvae.