interaction effects between weeds and seed priming on growth indices on different seed lots of seedy watermelon (citrullus lanatus)

background and objectives: seedy watermelon (citrullus lanatus) is a crop that is planted in as a second crop after winter crops some parts of country. this crop is more attended by farmers due to the short time between planting and maturity, low production costs and greater profitability rather than other spring crops. in order to evaluate the interaction effects between weeds and seed priming on growth indices on different seed lots of seedy watermelon (citrullus lanatus). materials and methods: this experiment was conducted in factorial design based on complete randomized block design with three replications in research farm of faculty of agriculture of ferdowsi university of mashhad in 2013. first factor included three seed lots of seedy watermelon (kalaleh, neishabour and bojnord), second factor included seed hydropriming in two levels (primed and non-primed seeds) and third factor was weedy and weed free conditions. the studied traits were include plant height, leaf area index, fruit setting, fruit number per plant, seed number per fruit, 1000weight and seed yield. results: results showed that weeds had effect on growth and yield components of seeds, which caused reduction in seed yield in seedy watermelon lots by 79%. seed priming reduced the effects of weeds on leaf area index and thousand kernel weights, but didn’t have any significant effect on seed yield, but increased seed yield rather than control treatment. in general, the most seed yield and thousand kernel weights were observed in neishabour lot with 1581 kg per ha and 144 gr, respectively. conclusion: based on the results of the experiment on weed interference all traits, especially grain decreased significantly with the removal o the weeds can be to a certain extent or in the presence official said grasses weeds can also be performed using the appropriate varieties as well (neishabour seed lots) as the preparation of seed germination as well as providing good condition (seed priming) can be achieved optimal performance.