Yield trials of lotus (Nelumbo nucifera Gaertn.) grown for seed production

Lotus (Nelumbo nucifera Gaertn.) is an aquatic plant that is a popular cash crop in Thailand. A major problem with cultivated lotus is the poor yield of harvested seeds in tropical regions because of low seed set. The aim of this study was to evaluate seed yield and seed quality in eight lotus cultivars (‘Nnu_A001’, ‘Nnu_A010’, ‘ChHy04’, ‘Khon Khen 6’, ‘Bang Phra 3/2’, ‘Prachuap Khiri Khan 29’, ‘Yasothon 1’ and a local cultivar). The study was conducted at the Si Sa Ket Horticultural Research Center, from October 2017 to September 2018. The lotus rhizomes were grown in an aquatic pond, with dimensions of 6 m in length, 1 m in width and 0.5 m in depth. The design was a randomized complete block design with three replications. Treatments were eight cultivars of lotus. ‘Nnu_A010’, ‘Prachuap Khiri Khan 29’, ‘Yasothon 1’ and the local cultivar showed the shortest times to first flowering at 86, 77, 80 and 83 days after planting, respectively. The greatest pod size, seed size and seed fresh weight occurred in ‘ChHy04’. The local lotus cultivar was found to have the highest number of seeds pod^‑1. However, ‘Yasothon 1’ had the highest percentage of normal seed and the highest seed yield. ‘ChHy04’, ‘Yasothon 1’ and the local cultivar were selected for evaluation under field conditions for further varietal improvement.