Effects of cultivars and pre plant and post emergence herbicides on yield, yield component of Pisum sativum

Weeds are a serious threat to peas and reduce the amount of its production. Pea plants due to slow growth and small size, has little competitive power and weeds can highly reduce its yield. Farmers are pushing for cheaper and easier alternatives, such as chemical control, because of the high cost of manual weeding. The purpose of this experiment was to investigate the tolerance of peas varieties including Shamshiri, Pofaki and Do-manzooreh against herbicides used in these fields as well as evaluation of their yield under different weed management treatments.

The experiment was conducted as factorial in a randomized complete block design with three replications in Kalaleh, Iran. The first factor was the weed management method, including the recommended dose of Trifluralin herbicides (2 L.ha-1, preplant), Imazthapyr (0.7 L.ha-1, post emergence), a mixture of two Bentazone (2 L.ha-1) and Haloxyfop-r-methyl (1 L.ha-1) and the application of Haloxyfop-r-methyl and Bentazon separately at intervals of one week with of the above doses, weeding and weedy, and the second factor was cultivars of peas including Shamshiri, Pofaki and Do-manzooreh. At the end of the growing season, 10 peas were selected from each plot, and number of pods per plant, number of seeds per pod, number of seeds per plant, green pod per plant, 100 seed weight and pod yield were measured. To determine the grain yield, the rest of the plot was harvested and generalized to the hectare. After normalizing the data in Minitab software they were analyzed by SAS software. The comparison of the mean of the data was done by the LSD test and the shapes were drawn in the Excel software.

The results showed that the highest number of pods per plant was obtained from Weed and Trifluralin treatments in the Domezorah cultivar, and the least of them were isolated from individual treatments of Bentazone and Haloxyfopromethylene. In the same cultivar, the highest values of the traits included the number of grains in pods, number of seeds per plant, green pod weight and 100 seed weight were recorded from weeding and Trifluralin treatments and the lowest values of these traits were obtained from separate treatments of Bentazone and Haloxyfop r methylene. The highest values related to the number of pods per plant and the number of seeds per plant were obtained from weeding treatment at cultivar Pofaki. The highest green weight of pod in Pofaki cultivar was obtained from weeding treatments and separate consumption of Bentazone and Haloxyfop-r-methylene. While the weight of 100 seeds in this cultivar was not affected by any management practices.In Shamshiri cultivar, the highest number of pods per plant, pod weight and 100 seed weight was obtained from Persuit treatment and the number of seeds per plant was highest in weed treatment.

Regarding the results of this study, it seems that the management of Trifluralin in Do-manzooreh cultivar has a better effect on weed control than the rest of the cultivars, while at the same time it has less adverse effects on this cultivar. In Pofaki cultivar, application of Trifluralin herbicide caused poor emergence of peas. Totally, Pofaki cultivar showed more susceptibility to herbicides than other two cultivars and in most cases, Weeding treatments showed better results than chemical treatments at this cultivar. In Shamshiri cultivar, the effectiveness of Persuit herbicide was higher than that of Trifluralin, so that the traits measured in this treatment were always more than other chemical practices.