Drought is one of the major abiotic stresses limiting lentil productivity in rainfed production systems. Specific rooting patterns can be associated with drought avoidance mechanisms that can be used in lentil breeding programs. In all, 252 co-dominant and dominant markers were used for Quantitative Trait Loci (QTL) analysis on 132 lentil recombinant inbred lines based on greenhouse experiments for root and shoot traits during two seasons under progressive drought-stressed conditions. Eighteen QTLs controlling a total of 14 root and shoot traits were identified. A QTL-hotspot genomic region related to a number of root and shoot characteristics associated with drought tolerance such as dry root biomass, root surface area, lateral root number, dry shoot biomass and shoot length was identified. Interestingly, a QTL related to root-shoot ratio, an important trait for drought avoidance, explaining the highest phenotypic variance of 27.6 % and 28.9 % for the two consecutive seasons, respectively, was detected. This QTL was closed to the co-dominant SNP marker TP6337 and also flanked by the two SNP TP518 and TP1280. An important QTL related to lateral root number was found close to TP3371 and flanked by TP5093 and TP6072 SNP markers. Also, a QTL associated with specific root length was identified close to TP1873 and flanked by F7XEM6b SRAP marker and TP1035 SNP marker. These two QTLs were detected in both seasons. Our results could be used for marker-assisted selection in lentil breeding programs targeting root and shoot characteristics conferring drought avoidance as an efficient alternative to slow and labour-intensive conventional breeding methods.

Lentil plays an important role for food and nutritional security. It is a sustainable source of protein, zinc, iron, prebiotic carbohydrates, and diverse health-promoting nutrients. This crop is widely cultivated in semi-arid marginal areas and exposed to various environmental stressors. Drought stress is the major abiotic stress that causes serious effects on lentil growth and development. Thus, it is imperative to set up innovative and sustainable solutions to reduce the adverse effects of drought on lentil crop. In this review, the agro-morphological, physiological, and biochemical effects of drought on lentil were highlighted. Furthermore, breeding and agronomic interventions to improve lentil performance in drought-prone environments were also discussed. Overall, drought disturbs lentil germination, photosynthesis, water relations, shoot and root growth, thereby reducing final yield. Conventional breeding programs have identified several sources of drought tolerance; however, modern biotechnological tools could be adopted to decipher the genetic architecture of drought tolerance in lentil to accelerate the genetic progress. Cost-affordable and eco-friendly agronomic practices may also contribute to minimize the negative consequences of drought stress. Smart exploitation of breeding approaches and agronomic practices could help overcome drought, improve lentil productivity, and increase the profitability of farmers in dry areas.

The use of high-performant varieties could help to improve the production of food legumes and thus meet the demand of the growing world population. However, long periods needed to develop new varieties through traditional breeding are a major obstacle. Thus, new techniques allowing faster genetic advance are needed. Speed breeding using longer periods of light exposure on plants, appears to be a good solution for accelerating plant life cycles and generation turnover. However, applying extended photoperiod causes plant stress and mortality due to lack of information on the adequate intensity to be used in speed breeding protocol. This study examines the impact of light intensity under speed breeding conditions on the development and growth of lentils and chickpeas, with a keen interest in enhancing genetic gain in these key food legumes. Four distinct levels of light intensity (T1: Green-house: 2000 µmol/m²/s; T2: 148–167 µmol/m²/s; T3: 111–129 µmol/m²/s; T4: 74–93 µmol/m²/s) under a photoperiod of 18 h of light and 6 h of darkness were tested in a growth chamber. Significant variation depending on light intensity was observed for plant height, total biomass, number of secondary stems, pods number, number of seeds per plant, growth rate, green canopy cover, time to flowering, time of pod set, time to maturity, vegetative stage length, reproduction stage length and seed filling stage length. Light intensity significantly influenced flowering/maturity and plant’s stress compared to normal conditions in green-house where flowering/maturity were around 67/97 days for lentil and 79/111 days for chickpea. Therefore, lentils in treatment 2 flowered and reached maturity in 30/45 days respectively, with high stress, while chickpeas in the same treatment did not flower. In contrast, treatment 4 showed interesting results, promoting optimal growth with low stress, and flowering/maturity in 27/46 days and 28/54 days, respectively for lentils and chickpeas. These results underline the crucial importance of light management in speed breeding to accelerate vegetative growth and phenology while allowing healthy growth conditions for plants to produce enough seeds for generation turnover.