Iranian Journal Pulses Research

Abstract Introduction
Legumes are the second most important source of human food after cereals and are considered the primary source of plant protein due to their high protein content. In addition to providing food for humans and livestock, legumes enhance the fertility of agricultural soils when grown in rotation with other crops, owing to their symbiosis with nitrogen-fixing bacteria. Common bean (Phaseolus vulgaris L.) is the most important legume used for direct human consumption. Achieving high seed yield is one of the main goals of cultivating this plant, and appropriate agronomic management practices-such as determining the sowing date, row spacing, plant spacing, and providing essential nutrients-result in high biological and economic performance. Therefore, in this experiment, to find solutions to increase the yield of local beans in Guilan province, the appropriate sowing date, sowing pattern, and the effect of boron foliar application on bean growth and yield were investigated.
 
Materials and Methods
This research was conducted as a factorial experiment in the form of a randomized complete block design (RCBD) with four replications during the spring and summer of 2023 in the Rudbaneh section of Lahijan, Iran. The factors examined in this experiment included sowing patterns at three levels: rectangle pattern (20×31 cm), rhombus pattern (23×27 cm), and square pattern (25×25 cm), with a constant density of approximately 16 plants per square meter. Additionally, foliar application of boron at a concentration of 0.1% was compared to no boron application. These factors were evaluated in two experiments conducted on April 25^th (spring) and August 29^th (summer).
 
Results and Discussion
The results of the combined variance analysis showed that the effect of the sowing date was significant on all tested traits except for seed protein content. These traits included plant height, number of secondary branches, number of pods per plant, percentage of fertile pods, 100-seed weight, biological yield, seed yield, seed formation rate, seed filling rate, yield formation rate, and vegetative growth rate. In contrast, sowing pattern treatments significantly affected only plant height, the number of secondary branches, and 100-seed weight, with no significant impact on the other measured traits. In comparison, boron foliar application had a significant effect on a wide range of traits, including plant height, number of pods per plant, percentage of fertile pods, 100-seed weight, biological yield, seed yield, seed formation rate, seed filling rate, yield formation rate, vegetative growth rate, and seed protein content. The results showed that seed yield at the spring sowing date averaged 348.3 g.m^-2, which was significantly higher than the summer sowing date average of 204.0 g.m^-2 (a 41% increase). Boron foliar application also significantly increased seed yield, with an average of 307.9 g.m^-2 compared to 244.5 g.m^-2 without boron (a 20% increase). However, sowing patterns had no significant effect on seed yield. The components of seed yield, including the number of pods per plant and 100-seed weight, were higher at the spring sowing date, with averages of 15.6 pods and 42.8 g, respectively. These values represented increases of 37% and 6%, respectively, compared to the summer sowing date. Boron foliar application also resulted in a 16% increase in the number of pods per plant and a 5% increase in 100-seed weight, with averages of 13.8 pods and 42.6 g, respectively, compared to no boron application. Additionally, the square sowing pattern achieved a higher 100-seed weight, averaging 41.8 g, compared to the rhombus and rectangle sowing patterns.
 
Conclusions
Based on the results of this experiment, sowing local beans of Guilan in the spring season, using the square sowing pattern, and applying boron foliar application were superior in terms of seed yield and growth indices compared to the summer sowing date, rectangle, and rhombus planting patterns, and no boron application.