Understanding resistance mechanisms in crop wild relatives (CWRs) of pigeonpea (Cajanus cajan L.) against pod borer Helicoverpa armigera (Hub.)

The pod borer, Helicoverpa armigera (Hübner), is a highly destructive pest of leguminous crops, particularly pigeonpea (Cajanus cajan L.). This crop suffers significant damage from H. armigera, with estimated yield losses ranging from 30 to 40% annually. Despite extensive screening of elite pigeonpea accessions from the primary gene pool for resistance, no stable and true resistant or tolerant accessions have been identified. In this study, we screened 96 pigeonpea accessions from diverse gene pools for resistance to H. armigera using larval (first and third instar larvae) antibiosis during Rainy-2022. Based on k-means clustering, 50% of these accessions were selected for further evaluation in Rainy-2023 under field and laboratory conditions. Notably, accessions of Cajanus scarabaeoides from the secondary gene pool—specifically ICP 15716, ICP 15718, and ICP 15726—exhibited the lowest pod damage ratings (3.0–3.6), lower per cent larval survival (26–46%), and reduced per cent larval weight gain (27.0–35.18%) over two seasons. In addition, Rhynchosia suaveolens (ICP 15867) from the quaternary gene pool also exhibited minimal damage rating and low larval weight gain. The correlation of pod damage and oviposition with pod trichome density, pod length and pod width revealed that these morphological traits are key factors in conferring resistance against H. armigera. The Multi-trait Genotype Ideotype Index (MGIDI) identified seven superior accessions of C. scarabaeoides—ICP 15718, ICP 15716, ICP 15726, ICP 15730, ICP 15744, ICP 15732, and ICP 15703—as optimal candidate accessions for future breeding programs. This study highlights the critical role of host plant resistance in developing resilient pigeonpea cultivars resistant to H. armigera and emphasizing the potential of utilizing wild relatives in crop improvement strategies

Institutional and technological innovations for sustained change in smallholder irrigation schemes in southern and Eastern Africa

Water management systems must become more adaptable to alleviate projected shortfalls. Integrated socio-institutional and technological interventions are required to generate sustained change in irrigation water management and the profitability for smallholders and their schemes. We illustrate this by conducting an ex-post analysis of the ‘Transforming Irrigation in Southern Africa’ (TISA) project, which was implemented in two phases from 2013 to 17 and 2017–2023. The project introduced institutional and technological innovations to smallholder irrigation schemes in Tanzania, Mozambique and Zimbabwe: Agricultural Innovation Platforms as a participatory approach to engage farmers and stakeholders; and soil moisture monitoring tools to support farmer learning. We hypothesised that these innovations, despite differing socioeconomic and biophysical conditions in the three countries, would work synergistically to improve farmers’ adaptive capacity and generate sustained change. In this paper, we test our hypotheses through a synthesis of peer-reviewed TISA literature, focussing on four smallholder irrigation schemes and five factors identified in the literature as critical for increasing farmers’ adaptive capacity. Drawing predominantly on household surveys administered at the beginning, middle and end of the TISA project, we analyse a set of relevant indicators linked to the five factors. In addition to many changes, we found changes in irrigation management, including a reduction in total water use to less than half pre-TISA levels. Further, the changes were sustained when the schemes transitioned from an intensive research-for-development phase into a more operational phase. This research also shows that when governments listen to farming communities and revise institutional arrangements, such as water scheduling and scheme constitutions, this fosters more sustainable irrigated agriculture. We conclude that when initiating development projects for sustained change within smallholder irrigation schemes policy makers and donors must commit sufficient project time and funding for both a development phase and a transition to an operational phase. Programs must take a participatory approach and support multiple interventions including both socio-institutional and technological interventions

Optimal Plot Size is Key to Reducing Variability Associated with Aflatoxin Contamination while Designing Field Screening Experiments

Aflatoxin contamination in peanuts can occur at pre-, post-harvest, and in storage. Breeding for aflatoxin resistance is a priority trait and an important component of integrated aflatoxin management. However, the progress is limited due to sampling and field screening protocols which often don’t produce reproducible results. To identify good resistance sources, a reliable screening protocol and a sampling strategy are critical. In this study, we attempted to determine an optimal plot size to reduce the field variability associated with measuring aflatoxin in peanuts sampled from small field plots. A total of 9 peanut genotypes, including six MAGIC population lines, one released variety, and two standard checks were sown in a field during post-rainy 2023-24. The standard checks consist of a known resistant variety (J11) and a known susceptible variety (JL 24). Each genotype was sown in a single row with a length of 70 m (with 0.5m spacing for every 6m) in a sick field at ICRISAT and each plot is divided into 40 subplots of 1.5 m length. The experiment followed a randomized complete block design (RCBD) with three replications. The plots were inoculated with toxigenic Aspergillus flavus strain three times during the crop growth period starting from 35 days after sowing with a 15-day interval. After harvest, pods from each of 40 subplots were collected separately for aflatoxin quantification through indirect competitive ELISA. Results indicate significant genotype differences (p=0.0001) but no significant difference (p=0.9029) among replications. The ideal plot size for minimizing standard error was 9m. Further experimentation and validation are required to see whether these results are reproducible

The role of genotyping in measuring improved variety adoption and impact: advances, challenges, and policy directions

Accurate measurement of agricultural technology adoption is critical for evaluating the effectiveness of investments in agricultural research and development. While household surveys have long served as the primary tool for tracking varietal adoption, growing evidence reveals systematic mismatches between self-reported and DNA verified varietal identity. These mismatches arise from distinct local and scientific varietal nomenclatures, complex seed systems, and high varietal release rates. This review examines the emerging role of genotyping, particularly DNA fingerprinting, as a complementary method for varietal identification and adoption measurement. Drawing on a growing body of studies across crops and geographies, we assess how DNA fingerprinting alters adoption estimates, reveals patterns of varietal misclassification, and enhances our understanding of seed system performance. We identify critical design considerations for implementing DNA fingerprinting at scale, including sampling strategies, reference library construction, and integration with standard household surveys. The review also highlights methodological innovations to reduce DNA fingerprinting costs and explores how fingerprinting can inform monitoring, evaluation, and scaling of agricultural innovations. Finally, we outline key research and policy priorities to mainstream DNA fingerprinting into national agricultural systems and to support more evidence-based, accountable, and equitable food policy

MEAN PERFORMANCE OF EXTRA-EARLY GENOTYPES OF PIGEON PEA (CAJANUS CAJAN L.) FOR NODULATION CAPACITY ALONG WITH THEIR MORPHOLOGICAL TRAITS

Pigeon pea (Cajanus cajan L.) is a vital legume crop known for its role in enhancing the sustainability of agricultural systems, particularly in semi-arid and resource-limited regions. Its ability to fix atmospheric nitrogen through symbiotic association with Rhizobium, by producing nodules should be explored further. The present investigation was carried out with 53 extra-early genotypes of pigeon pea during Kharif 2024 using completely randomized design (CRD) with three replications at ICRISAT, Patancheru. Significant variation was recorded for majority of traits. High GCV and PCV were observed for nodule dry weight followed by total number of nodules. High heritability along with high genetic advance as per cent of mean was observed for days to 50 per cent flowering, total number of nodules and nodule dry weight. The results indicated that higher plant dry weight was associated with higher nodule number and nodule weight along with better morphological traits. Among 53 genotypes studied ICPX 181018-B-SS3-SS1-1-B and ICPX 181028-B-SS22-SS1-1-B were found to have higher mean performance for all the observed characters

Identification of promising hybrids and opportunities for rapid selection through trait association, combining ability and gene action in the pearl millet (Pennisetum glaucum (L.) R.Br.) gene pool under rainfed conditions

The ICRISAT pearl millet B-line gene pool, crucial for Indian NARs partners and private seed companies, was assessed through 218 Line × Tester crosses using an alpha-lattice design alongside four hybrid checks. The study explored combining ability, gene action, hybrid selection and accelerated product advancement using trait associations and interdependencies. ANOVA revealed strong genotypic and location effects and genotype × environment interactions were significant. Grain yield correlated positively with plant height, panicle length, threshing ratio and days to 50 % flowering. Panicle yield per plot had a strong direct effect (0.962) on grain yield, with very high phenotypic (0.95) and genotypic (0.94) correlations. Key yield traits, including days to 50 % flowering (0.164), plant height (0.491) and panicle length (0.414), influenced grain yield indirectly through panicle yield per plot. Significant genetic variability among parental groups emphasized the role of both additive and non-additive genetic variance. Narrow-sense heritability was highest for productive tillers (84.00 %), days to 50 % flowering (65.67 %) and panicle girth (62.81 %). Inbreds ICMR 08888 (2.87), ICMB 10555 (2.81), ICMB 01666 (2.71), ICMB 08888 (2.41) and ICMB 11111 (2.16), exhibited strong positive GCA effects for grain yield. Hybrids ICPH213, ICPH265, ICPH273, ICPH321 and ICPH166 exhibited high SCA for grain yield and reduced days to 50 % flowering, indicating superior per-day productivity. A total of seventeen hybrids including ICPH033, ICPH189, ICPH197 and ICPH206, have been identified for large-scale evaluation based on their high yield potential and desirable market specific traits, such as adaptation to the A1 Zone, medium maturity, dual-purpose suitability, short plant type suited for the B Zone, large panicle size and excellent fodder yield. To optimize selection efficiency, “Product Rating Index”, a metric combining flowering duration and grain yield, is proposed for assessing wider adaptability potential. Additionally, prioritizing panicle yield per plot and threshing ratio over direct grain yield measurements is suggested, particularly in early-generation hybrid evaluations

Exploring rancidity in pearl millet flour: A lipidomic and biochemical approach

Pearl millet is a nutritious and climate-resilient cereal extensively grown in the arid and semi-arid regions of South Asia and Sub-Saharan Africa. Despite its exceptional nutritional qualities, pearl millet suffers from limited acceptance, partly due to the short shelf life of its milled flour. The stored flour quickly becomes rancid after 7–10 days due to the rancidity of fatty acids and oils caused by various factors, including enzymes and metal ions. In this study, we examined high iron (biofortified [ICMH-1202 (BF5) and Dhanashakti (BF6)] and regular [PA-9285 (NBF2) and MP-7872 (NBF4)] millet grain-based stored flour. Hydrolysis of triacylglycerols led to the accumulation of free fatty acids. Data on acid value, peroxide value, and enzymatic activities showed that high iron lines exhibit a higher rate of lipid oxidation and peroxidation after 45 days of storage. The biochemical profiling of these lines indicated that the high-iron and low-iron lines are comparable regarding rancidity-linked traits until 14 days after grinding for most surrogate traits. These findings suggest that iron-rich flour is likely more susceptible to rancidity than low-iron lines after 45 days of storage. The results indicate that high-iron varieties would not affect the general Indian practices of using flour within 14 days, but they may require post-harvest stabilization to enhance shelf life beyond two weeks. However, it is crucial to emphasize that iron-rich varieties are vital in addressing hunger and malnutrition. These exploratory results suggest that heat treatment could help improve the shelf life of iron-rich pearl millet grains on a smaller scale, but a better solution is still needed for large-scale commercialization and to monitor this key trait in released varieties without compromising their nutritional content

A Ralstonia effector RipAU impairs peanut AhSBT1.7 immunity for pathogenicity via AhPME-mediated cell wall degradation

Bacterial wilt caused by Ralstonia solanacearum is a devastating disease affecting a great many crops including peanut. The pathogen damages plants via secreting type Ш effector proteins (T3Es) into hosts for pathogenicity. Here, we characterized RipAU was among the most toxic effectors as ΔRipAU completely lost its pathogenicity to peanuts. A serine residue of RipAU is the critical site for cell death. The RipAU targeted a subtilisin-like protease (AhSBT1.7) in peanut and both protein moved into nucleus. Heterotic expression of AhSBT1.7 in transgenic tobacco and Arabidopsis thaliana significantly improved the resistance to R. solanacearum. The enhanced resistance was linked with the upregulating ERF1 defense marker genes and decreasing pectin methylesterase (PME) activity like PME2&4 in cell wall pathways. The RipAU played toxic effect by repressing R-gene, defense hormone signaling, and AhSBTs metabolic pathways but increasing PMEs expressions. Furthermore, we discovered AhSBT1.7 interacted with AhPME4 and was colocalized at nucleus. The AhPME speeded plants susceptibility to pathogen via mediated cell wall degradation, which inhibited by AhSBT1.7 but upregulated by RipAU. Collectively, RipAU impaired AhSBT1.7 defense for pathogenicity by using PME-mediated cell wall degradation. This study reveals the mechanism of RipAU pathogenicity and AhSBT1.7 resistance, highlighting peanut immunity to bacterial wilt for future improvement

Rapid Generation Advancement in Pulse Breeding: Opportunities, Constraints, and Prospects

Pulses form a vital element of the nutri-diet for the mankind. The present-day concerns worldwide involve attaining food and nutritional security while tackling the issues of climate change and population inflation on the other end. At this juncture, as researchers are laser-focused on enhancing output per unit area and resources, rapid generation advancement (RGA) techniques stand-alone as the attractive and feasible solution. This technique opened a new niche in the pulse breeding with their interventions currently applicable in pigeon pea, chickpea, soybean, pea, clover, common bean, narrow-leaved lupin, and faba bean. The technique proved to enhance the generations while positively reducing the seasonal preferences, cost, and resources utilized for field trials with a regulated tweak in the photoperiod, temperature, carbon dioxide, humidity, and management factors. Thus, this chapter forms a comprehensive understanding of the prospects of rapid generation advancement, its opportunities, and challenges in breeding of pulse crops

Agroinfiltration-mediated transient assay for rapid evaluation of constructs in pigeonpea

The process of generating stable transformants is time-consuming, labor-intensive, and genotype-dependent. In contrast, transient gene expression techniques, such as agroinfiltration, offer a rapid assessment of gene function and expression. Agroinfiltration, widely employed for studying gene function, has been extensively applied in leaf tissues of Nicotiana benthamiana and various other plant species. Despite its broad utility in various plants, to our knowledge, no prior investigation has been reported in pigeonpea. In this study, we developed an agroinfiltration method for transiently expressing a green fluorescent protein (mGFP5) reporter gene in four pigeonpea genotypes using syringe infiltration at the seedling stage under greenhouse conditions. The expression of the reporter gene mGFP5 was assessed at 72-, 96-, and 120 h post-infiltration (hpi). Additionally, we assessed the effect of morphogenic genes, specifically growth-regulating factor 4 (GRF4) and GRF-interacting factor 1 (GIF1), from both rice and pigeonpea on the expression of mGFP5 in four pigeonpea genotypes. Our findings demonstrate that OsGRF4-GIF1 led to enhanced mGFP5 expression compared to CcGRF4-GIF1 in four diverse pigeonpea genotypes. Fluorescence could be detected till 120 hpi. Furthermore, PCR, RT-PCR, and fluorescence quantification confirmed the presence and expression of mGFP5 at 72 hpi. Our results highlight the efficacy of agroinfiltration in quickly evaluating candidate genes in four genetically diverse pigeonpea genotypes, thereby reducing the time required for the initial assessment of constructs suitable for diverse molecular biology analyses