Investigating the diverse potential of a multi-purpose legume, Lablab purpureus (L.) Sweet, for smallholder production in East Africa

Abstract

Climate change is posing severe challenges in Africa, where resilient crops are urgently needed to withstand drought periods and unreliable rainfall. Multipurpose legume species, such as lablab (Lablab purpureus (L.) Sweet), have been under-utilized yet have the potential to overcome climate challenges. While lablab is native to Africa, there are few characterized varieties and it is under-utilized by smallholder farmers due to a lack of information and access to varieties. Knowledge is especially lacking on the performance of this crop by genotype, management, and environment. We conducted a two-year field study at two sites to evaluate 29 lablab cultivars under sole and maize intercrop management, with 14 cultivars selected for in-depth study. Cultivars were evaluated on vegetative biomass and grain yield production, with N fixation assessed for one site year. Biomass and grain production differed across environments and cultivars, with only biomass affected by intercropping. Average grain yield was substantially reduced to only 37 kg ha-1 in environments with maximum temperatures greater than 33˚C, but biomass production yielded comparable amounts across high temperatures and in dry (<500 mm rainfall) environments. Tradeoffs were found between biomass and grain yield across high yielding cultivars, with the top three grain accessions averaging 612 kg ha-1 of grain and 1.97 Mg ha-1 biomass whereas the top three biomass accessions produced 327 kg ha-1 grain and 2.52 Mg ha-1 biomass across all environments. In a comparison of production and N fixation measurements, cultivars were identified which may have high performance in both. Suitability of lablab for grain and biomass production were visualized across Tanzania in a map comparing max temperature thresholds for grain and biomass against average regional livestock populations. This provides a way forward for identifying potential areas for lablab cultivation as a novel means to enhance fodder and pulse production with smallholder farmers.

Estimating agronomically relevant symbiotic nitrogen fixation in green manure breeding programs

“…The Ndfa and total N per plant can be used to quantify the amount of N supplied through SNF and the amount scavenged from soil, which is crucial for N budgets. We found that plants with similar N content varied widely in Ndfa (Supplemental Figure S3), which is consistent with data from other legume species (Barbosa et al., 2018; Bliss, 1993; Dhanapal et al., 2015; Nord et al., 2020; Voisin et al., 2007). Variation in Ndfa means that the plant biomass or total N content does not reliably indicate how much N is provided by SNF.…”

Farmers’ Participatory Plant Selection of Lablab (Lablab purpureus (L.) Sweet) in Tanzania

“…The present study revealed that lablab was intercropped with maize and pigeon peas ( Table 2 ). Intercropping lablab with other crops improves yield ( Nord et al, 2020 ; Aluku et al, 2021 ), lowers insect pest abundance ( Forsythe, 2019 ), improves soil quality ( Maass et al, 2010 ), and maximizes the use of land resources ( Massawe et al, 2016 ). Cultivation of lablab as a sole crop occupies land space that can also be used for other crops.…”

“…Lablab production was mainly done during the long rain season that occurs between March and June. The production of lablab during long-rain seasons has also been reported (Nord et al, 2020;Aluku et al, 2021), with a tenfold increment in yield performance compared to cowpeas, pigeon peas and common beans. Other farmers are, however, involved in lablab production during the short-rain season since lablab a drought resistant crop is.…”

Recent developments in Lablab purpureus genomics: A focus on drought stress tolerance and use of genomic resources to develop stress‐resilient varieties

“…In Africa, only Kenya has commercialized its varieties: Eldo‐KT Black 1 and 2 (Eldoret Kirkhouse Trust black), Eldo‐KT cream, and Eldo‐KT Maridadi (KEPHIS, 2017; Kirkhouse Trust, 2015). Evaluation performance of the promising cultivars has also been taking place in Northern Tanzania towards their commercialization (Miller et al, 2018; Nord et al, 2020). The reason behind these few recommended varieties was research focusing more on morphological characterization, forage, and soil properties especially in Africa.…”