Evolutionary and Environmental Biology Seminar

By Dr. Amit Gur


Yield Heterosis in Melon is Regulated Above and Underground

Date &Time:

March 7, 2022


Safdie Auditorium, Multi-Purpose Building,
Amit Gur
Plant Science Institute, Agricultural Research Organization, Newe Ya’ar Research lamitgur@volcani.agri.gov.i Center, Ramat Yishay, Israel.
Yield is an important attribute of crop plants, particularly in light of global climate change and human population growth. Heterosis, the phenotypic superiority of hybrids over their parents is a major genetic force associated with plant fitness and crop yield enhancement. However, the potential of heterosis for yield improvement in melon is not fully explored.
In this seminar I will describe our ongoing effort to genetically dissect yield variation in Melon. Our core population is a set of 300 F1 hybrids resulting from crossing 25 diverse melon inbreds in a half-diallel mating scheme. Genomes of the 25 founders were sequenced and recently assembled de novo. In multiple yield trials, we found extensive best-parent yield heterosis that was explained by a shift in the significant tradeoff between yield components – fruit size and fruit number. To further explore the practical potential of heterosis for melon breeding, we looked underground and analyzed this population grafted as rootstocks with a common scion. We show that root-mediated yield heterosis is prominent in melon. The yield enhancement of the four best-performing hybrid rootstocks was validated in multiple experiments with four different scion varieties. Linkage-mapping of root-mediated yield QTLs is underway using bi-parental RILs population. While root biology is receiving increased attention, most of the research is conducted using plants not amenable to grafting and, as a result, it is difficult to separate root and shoot effects. Our grafting approach is complementary to the common roots genetics research path that focuses mainly on variation in root system architecture rather than the ultimate root-mediated whole-plant performance, and is a step towards discovery of candidate genes involved in root function and yield enhancement. We show that heterosis is an important and underutilized genetic component in melon, independently expressed above and underground.