[Paper Review] Biochemical mechanism of resistance in some Brassica genotypes against Lipaphis erysimi (Kaltenbach) (Homoptera: Aphididae)

Sarwan Kumar, Manjeet Kaur Sangha|arXiv (Cornell University)|Mar 23, 2017

Insect-Plant Interactions and Control13 references5 citations

TL;DR

This study identifies biochemical resistance mechanisms in Brassica genotypes against the aphid Lipaphis erysimi, revealing that higher levels of glucosinolates, total phenols, and ortho-dihydroxy phenols correlate with reduced aphid infestation. The resistant genotypes Eruca sativa T 27 and B. carinata DLSC 2 exhibited significantly lower aphid counts (4.7 and 20.9 per plant) and minimal yield loss (5.79% and 10.59%), confirming the protective role of these phytochemicals.

ABSTRACT

Two years study was carried out during 2006-07 and 2007-08 crop seasons to study the response of different genotypes of oilseeds Brassica to Lipaphis erysimi (Kaltenbach) infestation both under field and screen house conditions and to find out the relationship of various biochemical constituents to aphid infestation. Among the various genotypes, the population of L. erysimi was significantly high on Brassica rapa variety brown sarson cv. BSH 1 and B. rapa var. yellow sarson cv. YST 151 in unprotected set i.e. 53.7 and 52.3 aphids/ plant, respectively. However, it was the lowest on Eruca sativa cv. T 27 (4.7 aphids/plant) followed by B. carinata cv. DLSC 2 (20.9 aphids/ plant) which suffered the least yield loss i.e. 5.79 and 10.59 per cent, respectively. Almost similar trend was observed in seedling mortality, which was the maximum in BSH 1 and YST 151, while no seedling mortality was observed in the case of T 27 during both the years of study. Analysis of various biochemical constituents revealed that glucosinolates, total phenols and ortho-dihydroxy phenols had inverse relationship with the aphid infestation. Higher amount of these biochemical constituents in T 27 and DLSC 2 was responsible for lower aphid infestation on these genotypes.

Motivation & Objective

• To evaluate the resistance response of diverse Brassica genotypes to Lipaphis erysimi infestation under field and screen house conditions.
• To identify biochemical constituents linked to resistance against aphid attack.
• To correlate levels of specific phytochemicals with aphid population density and yield loss.
• To determine the role of glucosinolates, total phenols, and ortho-dihydroxy phenols in mediating resistance.

Proposed method

• Field and screen house experiments were conducted over two crop seasons (2006–2007 and 2007–2008) to assess aphid infestation on multiple Brassica genotypes.
• Aphid population counts were recorded per plant to quantify infestation levels across genotypes.
• Biochemical analysis measured concentrations of glucosinolates, total phenols, and ortho-dihydroxy phenols in leaf tissues.
• Yield loss and seedling mortality were assessed to evaluate the agronomic impact of aphid infestation.
• Statistical analysis examined the relationship between biochemical constituents and aphid population density.
• Correlation analysis determined the inverse relationship between resistance-related phytochemicals and aphid infestation.

Experimental results

Research questions

• RQ1 Which Brassica genotypes exhibit the lowest aphid infestation levels under field and screen house conditions?
• RQ2 What biochemical constituents are significantly correlated with reduced Lipaphis erysimi infestation?
• RQ3 How do glucosinolate, total phenol, and ortho-dihydroxy phenol levels relate to aphid population density?
• RQ4 To what extent do these phytochemicals influence yield loss and seedling mortality?
• RQ5 Can specific biochemical markers predict resistance to L. erysimi in Brassica species?

Key findings

• The genotype Eruca sativa cv. T 27 recorded the lowest aphid count at 4.7 aphids per plant, significantly lower than other genotypes.
• B. carinata cv. DLSC 2 had 20.9 aphids per plant and experienced only 10.59% yield loss, indicating strong resistance.
• Brassica rapa varieties BSH 1 and YST 151 had the highest aphid infestation (53.7 and 52.3 aphids/plant) and suffered the greatest yield loss.
• A strong inverse correlation was observed between glucosinolate, total phenol, and ortho-dihydroxy phenol levels and aphid population density.
• No seedling mortality was recorded in T 27, while BSH 1 and YST 151 showed the highest seedling mortality rates.
• The highest levels of resistance were associated with elevated concentrations of glucosinolates and phenolic compounds, particularly ortho-dihydroxy phenols.