Including predator presence in a refined model for assessing resistance of alfalfa cultivar to aphids

The aphid quantity ratio（AQR） is defined as the number of aphids on each cultivar divided by the number of aphids on all cultivars. AQR is based on the correlation between aphid populations and their host plants and is an important tool that has been utilized in evaluating Medicago sativa（alfalfa） cultivar resistance to aphids. However, assessment of alfalfa resistance to aphids can be confused by the presence of aphid predators, causing the assessment of plant resistance to aphids to be based on incorrect aphid population data. To refine the AQR and account for the effect of predators on aphid population assessments, we introduced a parameter ‘α＇, corresponding to the predator quantity ratio, and used αAQR as the ratio to quantify aphid populations. Populations of both aphids（4 species） and their predators（12 species） occurring in 28 M. sativa cultivars were sampled over two years at a research station near Cangzhou, Hebei Province, China. Results showed that the most suitable evaluation period was from May to June, as the aphid population was stable during this period. Compared with the AQR method, the predator population numbers based on the αAQR had a significant inverse relationship with aphid population numbers and the 28 cultivars were clustered into three classes： the resistant class, tolerant class, and susceptible class. In addition, 17 cultivars were reassigned when evaluated using αAQR. All numerical values calculated by αAQR were displayed as a Gaussian distribution, which showed that the 28 cultivars could be clustered into nine groups using a median value（±SE） of 1±0.1. Hence, ongoing alfalfa breeding trials will be assessed using the αAQR to establish a robust system that includes agronomic performance parameters in order to generalize the new method for further studies.

Improving a method for evaluating alfalfa cultivar resistance to thrips

The thrips quantity ratio（TQR） model is an important tool for evaluating crop resistance to thrips based on the correlation between thrips quantities and cultivars. Unfortunately, it is inaccurate, and the results appear significantly inconsistent when analysing the same cultivars in the same field study. To improve this model, we first studied the resistance of 28 alfalfa cultivars to thrips in Cangzhou, Hebei Province, north China. The results showed that the most suitable evaluation period was from May to June, as the thrips population was stable during this period. Second, we found that the natural enemy population was significantly positively correlated with the thrips population density（R=0.7275, P〈0.0001）, which might influence resistance estimation. Hence, we introduced a parameter ‘α＇, corresponding to the natural enemy quantity ratio, to eliminate the effect of the natural enemy using ＂αTQR＂. Using the improved method, 28 cultivars were clustered into three classes： the resistant class, sensitive class, and median class. All numerical values were calculated for αTQR displayed as a Gaussian distribution. This information showed that all data should be divided into nine groups using a median value of 1±0.1 with an equal difference of 0.1. Based on the new standard cultivars, Gongnong 1, Alfaking, Cangzhou and Algonquin were classified as highly resistant cultivars; Zhongmu 3, Gongnong 2, Zhongmu 1 and Zhongmu 2 were classified in the resistant group; Queen was classified in the moderately resistant group; Derby, WL354HQ, KRIMA, Apex, 53 HR, SARDI 5 and Farmers Treasure were classified in the median class; WL319HQ, WL343HQ and Sitel were classified as the low sensitive group; WL440 HQ and SARDI7 as the moderately sensitive group; WL168HQ and Sanditi as the sensitive group; and SARDI 10, WL363HQ, FD4, WL323 and SOCA as the highly sensitive group.

Natural Resistance of Two Plantation Woods Populus × canadensis cv. and Cunninghamia lanceolata to Decay Fungi and Termites

Natural durability of two plantation woods, Chinese fir and I-214 poplar, was investigated thoroughly by three test- ing methods, namely an accelerated laboratory decay test, a fungus cellar test and a field test. After the decay test using Postia pla- centa and Trametes versicolor, Chinese fir and the I-214 poplar showed 34% and 69% of mass loss, respectively, indicating they should be classified as slightly durable and non-durable wood. This conclusion was confirmed by the fungus cellar test and the field test. Like the performance in the decay test, I-214 poplar showed no resistance to termites either in the laboratory or in the field, whereas Chinese fir would be classified as moderately resistant.

Influence of Additional Feeding of Sucrose Goat Females on Indicators of Natural Resistance of the Body and Productivity of Kids

The traditional way of breeding pastured animals is year-round pasture keeping without any additional fertilizing. Recently, among adult animals and the resulting offspring, a large number of individuals with low levels of natural resistance have begun to appear, which negatively affects the productivity of adults, and growth and development, as well as the safety of the resulting offspring. In this regard, the aim of the study was to study the effects of full-fledged feeding of females during pregnancy on the level of natural resistance of the received goats. To achieve this goal, a number of modern physiological and biochemical research methods were used. According to the results obtained, it was established that with the organization of full-fledged feeding, the period of suckling of the goat develops normally and the resulting baby goats are born with increased levels of natural resistance and more massive. In the goats of the experimental group, these advantages persist steadily until the age of one year, and to a certain extent ensure the normal preservation of the received goats and their growth and development. This makes it possible for farmers to fatten goats unused in breeding from 8 - 9 months of age and donate them for meat as an additional economic supplement to production.

Ecological Consequences of Mechanization of the Wood Skidding Works in Greece

The movement of the wood skidding means on the natural ground causes damages in the soil and in the remaining stand, the size of which depends on the kind, the resistance and the soil conditions, from the size and movements frequency on the machines as well as from the length of the skidding wood. This study was carried out in a productive forest of Greece, the resistance of the soil in connection with the moisture and the category of the native stone, the pressure that tires of tractors exert in the soil, are estimated. It also estimated the percentage of the trees in the remaining stand which suffer damages from the movement of various means. The above means are used for the skidding of wood of different lengths. According to the results of the research some measures are suggested so as to decrease the damages, which are caused in the soil and in the remaining stand.

A natural allele of Bsr-d1 in rice confers broad-spectrum blast resistance

Subject Code:C14With support from the National Natural Science Foundation of China,a collaborative research group led by Prof.Chen Xuewei(陈学伟)of the Rice Research Institute,Sichuan Agricultural University,published an article entitled“A natural allele of a transcription factor in rice confers broad-spectrum