Effects of suboptimal low temperatures on plant architecture and flowering in muskmelons Cucumis melo L.

The effects of suboptimal cold temperatures were investigated in an array of vegetative, reproductive and leaf characters in 34 cultivars, both open pollinated and hybrid, of melons, Cucumis melo. The cultivars were grown in two treatments: (i) a heated greenhouse (T1) that produced temperatures similar to those used in commercial cultivation in winter; and (ii) an unheated greenhouse (T2) that produced significantly lower night-time temperatures than T1. Plants grown in T1 had significantly longer main stems and internode lengths, more nodes and more potassium in their leaves but less leaf biomass than plants grown in T2. Plants from T2 also had more green and yellow leaf colour than plants from T1. Open pollinated cultivars had significantly longer main stems, more nodes and more green and yellow leaf colour than hybrid cultivars. Significant differences were found among the cultivars in all traits.