A modified ear‐to‐row selection program in corn Zea maya L.) was initiated in Nebraska by Dr. J. H. Lonnquist in 1961. This paper describes results through the 10th cycle. Grain yields have continued to increase through the 10th cycle, but there is some evidence of curvilinearity. Part of this might be the result of a change in the selection criterion after the seventh cycle. At that time we began using a selection index that included lodging and dropped ears in addition to yield. The authors feel that it is unlikely that the selection study is plateaulng and therefore feel that linear regression estimates of gain are still appropriate. Gains in yield reported here from such an estimate are at the rate of 5.26% per cycle. Correlated responses in lodging, moisture at harvest, ear height, and number of ears per plant are discussed. Yield gains, though not very large, are still larger than those from mass selection in the same cultivar.

Predatory hornets are considered as one of the major constraints to beekeeping industry. Therefore, its incidence and predation rate was studied throughout the year at two locations- rural and forest areas of mid-hill in Laliptur district during 2016/017 to 2017/018. Observation was made on the number of hornet and honey bee captured by hornet in three different times of the day for three continuous minutes every fortnightly on five honeybee colonies. During the study period, major hornet species captured around the honeybee apiary at both locations were, Vespa velutina Lepeletier, Vespa basalis Smith, Vespa tropica (Linnaeus) and Vespa mandarina Smith. The hornet incidence varied significantly between the years and locations along with different observation dates. Their incidence and predation rates were low in early spring and summer that gradually increased with the highest peak in October and November in both locations. The maximum predation was on mid-November (62.07%) and early-November (53.49%) at rural and forest locations, respectively during 2016/017. In 2017/018, the highest predation was on early-November (70.27%) at rural area while it was in mid-November (58.62%) in the apiaries near the forest area. The population of hornet was considerably higher at forest areas and their incidence around the honeybee apiaries were negatively correlated with rainfall. Hence, assessment of the temporal and spatial population variations and predation rates along with weather parameters is helpful in to develop sustainable management plans of the hornet in apiary.

Background: Integrated Pest Management (IPM) is an approach for plant protection that was de­signed to reduce the need of chemical control. It is a complex, knowledge-based technology that combines biological, cultural and chemical control methods to keep pests below economically acceptable level. This study was done to assess the impact of IPM technology on pesticides use and yield of vegetable crops.Methods: A total of five hundred vegetable grower farmers from Banke and Surkhet districts of Lumbini and Karnali provinces, respectively, were purposively selected as the study area. These districts are the major vegetable growing areas in Nepal. Yield function was developed in estimating the functional relationship. Pesticide input was used as independent variable to know the effect of pesticide on vegetable yield. To detect the impact of IPM-technology on vegetable yield linear regression was used in this study.Result: IPM practicing farmers were significantly younger and more educated than control farmers. Pesticides and bio-pesticides were the major inputs used for controlling pests and diseases. Based on the sign and coefficient of the IPM (practice) variable, it has been concluded that use of IPM has positive and significant effect on the net revenue from the vegetables.

No abstract

No abstract