Growth conditions and phenotypic analysis
Seeds of the wild type, rms3-1 , rms4-1 , rms1-2 andrms5-3 pea mutants were allowed to germinate in vermiculite for 5 days. Thereafter six seedlings of each genotype were transferred to Levington F2 compost (Evergreen Garden Care Ltd.) in pots with a top diameter of 14 cm, 9.4 cm bottom diameter and a height of 12 cm equating to a pot volume of 1.3 L. These plants were used for experiments 28 days or less in duration. When plants were grown for 32 days, seven seedlings were planted in pots with an 18 cm top diameter, 13 cm bottom diameter, a height of 16.5 cm and volume of 3.14 L. Plants were grown in controlled environment chambers at 21ᵒC, 14h/10 day/night regime, 70% humidity and either at ambient CO2 or 750±50 ppm CO2 in a Microclima growth cabinet (Snijders Labs). Plant height and branching were determined at day 7, 14 and 32 after transplanting. Height was determined by measuring the stem from the soil to the apical shoot. Total branching was calculated as the sum of the height and length of each branch, not including branches shorter than 5 mm. Fresh and dry plant weight was determined at 28 days after transplanting, while dry weight was determined at 32 days.