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Khan S.,Balochistan Agricultural Research Center | Khan J.,Balochistan Agricultural Research Center | Khetran M.A.,Balochistan Agricultural Research Center | Hanan A.,Balochistan Agricultural Research Center | And 4 more authors.
Journal of Animal and Plant Sciences | Year: 2014

Five wheat genotypes including local wheat as a check were tested for grain yield stability at three different locations under rained conditions during 2006-07 in highland of Balochistan, Pakistan. These genotypes were exposed to different soil type, soil fertility, moisture levels and temperature. The G × E interaction mean squares were non-significant for grain yield. The mean square due to pooled deviations were, however highly significant indicating significant difference among five genotypes for non liner response. The overall mean grain yield performance of genotypes across environments ranged from 1198 to 2203 kg/ha. The stability parameters indicated regression coefficient (bi) value ranging from 0.998 in AZRC-3 to 1.004 in local wheat cultivar. Cultivar AZRC-3 having by values close to unity with higher grain yield showed consistent performance under different environments and considered as stable and widely adopted. This cultivar also showed the ideal stable performance with regard to mean grain yield of 2203 kg/ha, regression coefficient value of 0.998 and dispersion value of 0.002 followed by cultivar AZRC-2 (1999 kg/ha) with regression coefficient value of 0.999 and dispersion value (0.000). Based on bi and S2d values cultivar AZRC-4 was found to be stable for specific adaptation in favorable environments and produced good yield with regression coefficient > 1.0. Whereas, cultivars AZRC-1, AZRC-2 and AZRC-3 having values close to unity with higher grain yield showed consistent performance over different environments and could be considered as stable and widely adapted.

Hanan A.,Balochistan Agricultural Research Center | He X.Z.,Massey University | Shakeel M.,Pakistan Agricultural Research Council | Khetran M.A.,Balochistan Agricultural Research Center | Wang Q.,Massey University
Biological Control | Year: 2015

Eretmocerus warrae Nauman and Schmidt (Hymenoptera: Aphelinidae) is an important ecto-endoparasitoid of greenhouse whitefly Trialeurodes vaporariorum (Westwood) (Homoptera: Aleyrodidae). However, prior to the present study little was known about its life history strategies, making it difficult to develop a biological control program with this parasitoid. Using T. vaporariorum as hosts we carried out a series of experiments in the laboratory to determine the host stage preference by the foraging adults and its effect on the fitness of both adults and their offspring. The parasitoid females prefer to feed on and parasitize the second and third instar nymphs to gain maximal fitness for themselves and their offspring. Among the optimal hosts attacked, E. warrae allocate >80% of them for parasitization and <20% for feeding. The first instar larvae do not penetrate the host nymphs until the latter molt into the fourth instar regardless of the host stages parasitized. Therefore, after penetration all juveniles live in similar environment, feed on hosts with similar quality and quantity of nutrition, and achieve similar survival rate. The lower fitness gain and higher mortality of E. warrae juveniles when the first instar hosts are parasitized result from longer waiting time and starvation before penetration. The higher mortality of E. warrae juveniles if the fourth instar nymphs are attacked may stem from the fact that when E. warrae eggs hatch, the host nymphs have already developed to the pharate adult stage which the first instar larvae have difficulty penetrating. © 2015 Elsevier Inc.

Hanan A.,Balochistan Agricultural Research Center | Hanan A.,Massey University | He X.Z.,Massey University | Shakeel M.,Massey University | And 3 more authors.
Journal of the Entomological Research Society | Year: 2015

Eretmocerus warrae (Naumann and Schimdt) is a thelytokous aphelinid parasitoid of the greenhouse whitefly, Trialeurodes vaporariorum (Westwood). It was first detected in New Zealand in 1997 during a survey of greenhouses in Auckland. We investigated the effects of certain duration of food and host deprivation after emergence on feeding, oviposition behavior and egg resorption of E. warrae with seven treatments (0, 5, 10, 15, 20 and 25 hours of food deprivation, and 24 hours of honey feeding) before being used for the experiment. The experiments were conducted at Institute of Natural Resources, Massey University, Palmerston North, New Zealand. Under 22±1°C, 60±5% RH and 16:8 h light:dark. Results indicated that the parasitoids deprived of food and hosts for 5 hours laid significantly more eggs, lived significantly longer and fed on and parasitised significantly more hosts (P<0.0001). With the increase in food and host deprivation period from 5 to 25 hours the average daily host feeding rate significantly increased (P<0.0001). Significant egg resorption was detected after 3 days of food and host deprivation (P<0.0001). However, in honey fed parasitoids, significant egg resorption occurred after 6 days of host deprivation (P<0.0001). This study suggests that food and host deprivation for 5 h is the optimal period for host feeding, fecundity and longevity in E. warrae.

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