Pod Trichome Characterisation Using Foldscope, Morphological Characterization and Genetic Diversity Among Indigenous Collections of Pigeonpea [Cajanus cajan (L.) Millsp.]

Author(s):  
K. Satish ◽  
S. Muniswamy ◽  
G. Girish ◽  
Vikas Kulkarni ◽  
J.R. Diwan ◽  
...  

Background: Association of several morphological traits such as trichome length and trichome density on the pod surface have been found to influence host plant resistance to insect pests. Genetic diversity analysis is used to identify the divergent genotypes and to utilize these genotypes to exploit heterosis. Further, morphological characters are stable across environments owing to oligogeneic nature, they serve as morphological markers in breeding which can be used in varietal or genotypic identification, varietal purification and even in seed production. Hence, the current study aimed to investigate on host plant resistance using portable paper microscope ‘foldscope’, genetic diversity and morphological characters.Methods: A total of 154 germplasm lines with three checks were evaluated in Augmented Block Design (ABD) at Zonal Agricultural Research Station (ZARS), Kalaburagi, during kharif, 2018 to study their genetic diversity. Trichome length and trichome density were recorded using ‘foldscope’ 75 randomly selected genotypes, then correlated with shrivelled seed yield per plot due to pod fly incidence. Morphological characterization of 14 qualitative traits were recorded.Result: Grouping of 157 germplasm lines into twelve clusters indicated a wider genetic diversity for the traits studied, of which 7 clusters were solitary with one entry each. The genotypes with more trichome density and length had less damage by the pod fly. Large variations for morphological characters was observed among the genotypes for qualitative traits such as pod colour, stem colour, flower colour, seed morphology and pod trichomes. 

Author(s):  
B.L. Jat ◽  
K.K. Dahiya ◽  
H.C. Sharma

Background: The legume pod borer, Helicoverpa armigera (Hübner), is one of the most damaging crop pests, including pigeonpea. Host plant resistance is a component of pest management and therefore, we standardize a nylon bag No-Choice Bioassay technique to screen for resistance to H. armigera under field conditions. Methods: Pigeonpea plants were infested with 24 h old 1, 2, 3, 4 and 5 larvae per plant inside the nylon bag. Observations were recorded on pod damage, larval survival, larval weight, pupation, adult emergence, and fecundity after 10 days. Result: Pigeonpea varieties AL-201, H03-41 and PAU-881 exhibited lower pod damage (15.89 to 19.77%) and larval weight (12.02 to 13.82 mg). The expression of resistance to H. armigera was associated with trichome density, pod wall thickness and higher amount of phenolic compounds and condensed tannins. Lower trichome density and thin pod walls and higher amounts of sugars rendered the varieties Paras, Manak and Pussa-992 more susceptible to H. armigera. Nylon bag assay can be used to screen and select pigeonpea cultivars for resistance to H. armigera.


2021 ◽  
Vol 3 (1) ◽  
pp. 23-29
Author(s):  
Sitesh Chatterjee ◽  
◽  
Chirasree Gangopadhyay ◽  
Indrani Dana ◽  
Santosh Kumar Roy ◽  
...  

Rice plant is attacked by many insect-pests of which yellow stem borer (dead heart at vegetative stage and white ear head at reproductive stage) and leaf folder are considered as prime devastator, responsible for major economic loss. To combat this problem, resistant varieties of rice are required for better production as well as better productivity. Host plant resistance is very much effective in integrated pest management (IPM) system, where negligible pesticidal hazard is present as well as environmental safety, low cost farming by without or minimum pesticide application and proper identification of resistant varieties for selection as parent in crossing programme to develop resistant varieties in future. The 78 rice varieties were screened out against Scirpophaga incertulas (yellow stem borer) and Cnaphalocrocis medinalis (rice leaf folder) of rice during Kharif, 2010-2012 at Rice Research Station, Chinsurah, Hooghly, under Government of West Bengal. The experiment was carried out to determine the level of resistance in early, mid-early, medium and late duration rice varieties, and shallow and semi-deep rice varieties. The pest infestation level was determined by counting dead heart, white ear head and damaged/folded leaves. The experimental results revealed that the early duration variety viz. Narendra 97 and IR 50, the mid-early duration variety i.e. IR 64 and IET 17904 proved resistant against both yellow stem borer (dead heart) and leaf folder. The medium duration variety, Ranjit was highly resistant against both yellow stem borer (dead heart) and leaf folder, and the variety, Pratiksha showed a fair degree of resistance against both yellow stem borer and leaf folder; while Jarava, the late duration variety exhibited high degree resistance against yellow stem borer (dead heart and white ear head). Besides, the varieties, Sashi and Giri recorded very low level of infestation of both lepidopteran pests while shallow and semi-deep variety such as Sashi was also considered resistant against the noxious pests.


2010 ◽  
Vol 100 (6) ◽  
pp. 727-734 ◽  
Author(s):  
A.P. Michel ◽  
W. Zhang ◽  
M.A. Rouf Mian

AbstractThe soybean aphid, Aphis glycines Matsumura, is a recent invasive pest of soybean in North America. Currently, much research is focused on developing and characterizing soybean cultivars expressing host-plant resistance. During the initial phases of host-plant resistance screening, many of these studies use soybean aphid laboratory populations. Previous studies in other systems have documented substantial differences among laboratory and field populations. Whether or not this pattern exists in A. glycines is unknown, but it is extremely important when estimating the level of selection and virulence to host-plant resistant soybeans. In this study, we used seven microsatellite markers to estimate and compare genetic diversity and differentiation among five laboratory and 12 field populations. Our results indicate that soybean aphid laboratory populations are severely lacking in genotypic diversity and show extreme genetic differentiation among each other and to field populations. Continued use of laboratory populations for initial soybean aphid resistance screening could lead to erroneous estimations of the potential success for host-plant resistance.


2020 ◽  
Vol 49 (1) ◽  
pp. 88-97 ◽  
Author(s):  
S Lahiri ◽  
D D Reisig ◽  
F P F Reay-Jones ◽  
J K Greene ◽  
T E Carter ◽  
...  

Abstract Megacopta cribraria (F.) (Hemiptera: Plataspidae) is an invasive pest of soybean that has spread across the southeastern United States since its initial discovery in 2009 in Georgia. Previous studies in the southeastern states have documented both the population dynamics of this pest and host plant resistance (HPR) among soybean varieties, although the specific mechanisms of HPR remain unknown. The objectives of this study were, therefore, to 1) quantify field resistance to M. cribraria in multiple soybean varieties in two states previously affected by severe M. cribraria infestations, North Carolina (NC) and South Carolina (SC); and 2) study the role of soybean trichome density in imparting resistance against M. cribraria. Soybean variety ‘Camp’ was least attractive to M. cribraria, through time and locations, suggesting consistent resistance. Other varieties showed variable performance among the locations and sampling dates. A significant difference in trichome density was evident. However, there was no correlation between trichome density and M. cribraria infestation. Compared to a previously published study in the same location, when M. cribraria adults emerging from overwintering dispersed into soybeans, in our study only first-generation adults dispersed into soybeans. Considering the current trend of significantly lower M. cribraria infestation rates in North and South Carolina, this pest may be finally succumbing to indigenous natural enemies and should be managed by incorporating integrated pest management tactics, such as HPR, that help conserve natural enemy populations.


Plants ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1384
Author(s):  
Dinar S. C. Wahyuni ◽  
Young Hae Choi ◽  
Kirsten A. Leiss ◽  
Peter G. L. Klinkhamer

Understanding the mechanisms involved in host plant resistance opens the way for improved resistance breeding programs by using the traits involved as markers. Pest management is a major problem in cultivation of ornamentals. Gladiolus (Gladiolus hybridus L.) is an economically important ornamental in the Netherlands. Gladiolus is especially sensitive to attack by western flower thrips (Frankliniella occidentalis (Pergande) (Thysanoptera:Thripidae)). The objective of this study was, therefore, to investigate morphological and chemical markers for resistance breeding to western flower thrips in Gladiolus varieties. We measured thrips damage of 14 Gladiolus varieties in a whole-plant thrips bioassay and related this to morphological traits with a focus on papillae density. Moreover, we studied chemical host plant resistance to using an eco-metabolomic approach comparing the 1H NMR profiles of thrips resistant and susceptible varieties representing a broad range of papillae densities. Thrips damage varied strongly among varieties: the most susceptible variety showed 130 times more damage than the most resistant one. Varieties with low thrips damage had shorter mesophylls and epidermal cells, as well as a higher density of epicuticular papillae. All three traits related to thrips damage were highly correlated with each other. We observed a number of metabolites related to resistance against thrips: two unidentified triterpenoid saponins and the amino acids alanine and threonine. All these compounds were highly correlated amongst each other as well as to the density of papillae. These correlations suggest that papillae are involved in resistance to thrips by producing and/or storing compounds causing thrips resistance. Although it is not possible to distinguish the individual effects of morphological and chemical traits statistically, our results show that papillae density is an easy marker in Gladiolus-breeding programs targeted at increased resistance to thrips.


2021 ◽  
Vol 22 (11) ◽  
pp. 5941
Author(s):  
Abigail Ngugi-Dawit ◽  
Isaac Njaci ◽  
Thomas J.V. Higgins ◽  
Brett Williams ◽  
Sita R. Ghimire ◽  
...  

Pigeonpea [Cajanus cajan (L.) Millspaugh] is an economically important legume playing a crucial role in the semi-arid tropics. Pigeonpea is susceptible to Helicoverpa armigera (Hübner), which causes devastating yield losses. This pest is developing resistance to many commercially available insecticides. Therefore, crop wild relatives of pigeonpea, are being considered as potential sources of genes to expand the genetic base of cultivated pigeonpea to improve traits such as host plant resistance to pests and pathogens. Quantitative proteomic analysis was conducted using the tandem mass tag platform to identify differentially abundant proteins between IBS 3471 and ICPL 87 tolerant accession and susceptible variety to H. armigera, respectively. Leaf proteome were analysed at the vegetative and flowering/podding growth stages. H. armigera tolerance in IBS 3471 appeared to be related to enhanced defence responses, such as changes in secondary metabolite precursors, antioxidants, and the phenylpropanoid pathway. The development of larvae fed on an artificial diet with IBS 3471 lyophilised leaves showed similar inhibition with those fed on an artificial diet with quercetin concentrations with 32 mg/25 g of artificial diet. DAB staining (3,3’-diaminobenzidine) revealed a rapid accumulation of reactive oxygen species in IBS 3471. We conclude that IBS 3471 is an ideal candidate for improving the genetic base of cultivated pigeonpea, including traits for host plant resistance.


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