Can wild species improve symbiotic nitrogen fixation in the lentil crop?

    Nitrogen fixation is a symbiotic relation between legumes and Rhizobium that allows the bacteria to convert atmospheric nitrogen to other molecules (like ammonia) for the plant, and the plant to provide the bacteria with carbohydrates in exchange.  We now know that this process provides many great benefits to the health of our soil and crops.   

    The effectiveness/intensity of the nitrogen fixation process is dependent on both the bacteria and the legume plant under specific environment.  Wild species have contributed to the lentil crop with tolerance and resistance to biotic and abiotic stresses. We believe that our modern lentil varieties are "lazy fixer" as compared to their wild relatives, as they are bred under high fertility conditions and there is no need for them to establish relations with the rhizosphere. 

    To test this hypothesis, we are exploring 6 wild lentil species as well as a group of cultivated lentils to characterize their nitrogen fixing ability. The purpose is to identify specific genotypes with higher ability and to better understand potential contributions of wild plants to the domesticated lentil.

Materials/Populations:

CDC Redberry, CDC Maxim, CDC Robin, CDC Milestone, CDC Asterix, CDC KR1, Eston, Greenstar, VIR 421, QG 4, Lupa, ILL 1704, ILL 7502, ILL 8006, Indian head (L. culinaris)

BGEO 16880, IG 72529, IG 72611, IG 72622, IG 72643, IG 72672, PI 572376 (L. orientalis)

IG 72613, IG 72614, IG 72805, PI 572390 (L. tomentosus)

IG 72543, IG 72623, IG 72760 (L. odomensis)

IG 110810, IG 110813, IG 72537 (L. lamottei)

IG 72815, L01-827A, LR59-81 (L. ervoides)

IG 116024 (L. nigricans)

LR-84 (cv. Redberry x L. orientalis PI 572376)

Locations:

Saskatchewan

Phenotyping:

Photosynthesis related parameters: relative chlorophyll, Phi2, PhiNO, PhiNPQ

Shoot dry weight, root dry weight, N content

Nodulation: number, color-scale (1=white, green, yellow, 2=predominantly pink, 3= pink)

Root traits: Total length, area, average diameter, length per volume, volume

Genotyping:

QTL mapping X

Results:

The genotype PI 572376 (L. orientalis) fixes the highest amount of Nitrogen/gram dry matter within the evaluated genotypes. Study of 36 Lens genotypes inoculated with a commercial R. leguminosarum strain in cylinders system and nodulated roots at flowering stage.

Who is working on this?

Ana Vargas 

Douglas Cook (UCDavis)

Brendan Riely (UCDavis)