An innovative natural speed breeding technique for accelerated chickpea (Cicer arietinum L.) generation turnover

The slow breeding cycle presents a significant challenge in legume research and breeding. While current speed breeding (SB) methods promise faster plant turnover, they encounter space limitations and high costs. Enclosed environments risk pest and disease outbreaks, and supplying water and electricity remains challenging in many developing nations. Here, we propose an innovative natural speed breeding (nSB) approach to achieve two generation cycles per rabi season under natural open field conditions in chickpea. This cost-effective, environmentally friendly method offers a location-specific alternative to prevalent SB techniques.

Two field experiments were conducted. First, 11-day-old fresh immature green (FIG) seeds exhibited an 80% germination rate, reducing the duration of the breeding cycle by 14%. In second, abiotic stresses such as atmospheric, nutrient, soil, and water stresses reduced the duration of the breeding cycle by 40%, 18%, 15%, and 18%, respectively. Despite the shortened generation time, we consistently obtained a minimum of 4-6 pods plant^-1, ensuring continuity in the subsequent breeding cycle without compromising the nSB process.

Our investigation revealed that the combination of this location advantage (40%) with the sowing of FIG seeds (14%) enables Baramati to achieve progress from F2 to F5 in 1.5 years, with two generation cycles per rabi (cool) season. Using the nSB method can save 3 years, marking a notable reduction from the conventional six-year timeline. Moreover, incorporating the additional abiotic stresses mentioned above will further reduce the generation advancement time. Therefore, nSB accelerates generation turnover and reduces varietal improvement time at a low cost.