¹Faculty of Agriculture, Universitas Gadjah Mada

²Faculty of Biology, Universitas Gadjah Mada Bulaksumur, Sleman 55281, Yogyakarta, Indonesia

Email: sarlin.kusumaningrum@mail.ugm.ac.id

The mechanisms of fruit formation on the growth of chilli plants are the results of both direct and indirect processes. The roots and shoots interact in their growth and function. These interactions undoubtedly reflect the interdependence of each organ for their fruit formation. This research was aimed to determine direct and indirect relationship between root and shoot on fresh weight fruit formation to four lowland chilli varieties. This study was designed using a randomized, complete block design (RCBD) consisted of 4 levels varieties namely Lembang-1, Kencana, Tanjung-2, dan Ungara. The results showed that fruit weight Tanjung-2 variety directly influenced by root lenght, dry weight root, leaf area, and plant height. Similarly, photosynthesis and transpiration rate in Kencana variety was indirect effect, while root lenght, root area, leaf area, and assimilate accumulation in root and shoot was directly effect to fresh weight fruit.  In Lembang-1 variety,  root conditions directly affected on photosynthesis rate, accumulation of nitrate reductase activity, plant height, and number of branch so that it affacted fresh weight fruit.  Ungara variety fresh weight fruit can be affacted indirectly root lenght and nitrate reductase activity, but accumulation assimilate in root and clorophyll content was directly effect. It is concluded that fresh weight of four lowland chilli varieties had different responses to formation process.