Winter Legumes for Direct Seeding Systems

 

F.J. Muehlbauer, Legume Breeder, U.S. Department of Agriculture, Agricultural Research Service and The Department of Crop and Soil Sciences, Washington State University, Pullman, Washington USA 99164-6434

 

Introduction.

Winter hardy peas and lentils for direct seeding in standing cereal crop stubble are expected to contribute to solving the erosion problem while producing higher yields at reduced costs. Being established in the fall enables the crop to begin early vegetative growth prior to freezing temperatures and to resume vegetative growth immediately after temperatures rise in spring. The crop therefore benefits by completing vegetative growth stages during the cooler and more humid periods when evaporation and transpiration is minimal. That beneficial time period varies with elevation and latitude. In areas where fall sowing of peas has been successful, the crop is expected to produce significantly more yield as compared to spring planted varieties (Table 1). Extremes of cold, time and density of planting, soil water logging, and diseases reduce winter survival and yields.

Tillage practices designed to retain residues from previous crops, maintenance of surface roughness to aid in snow capture, and choice of fields that have good internal drainage are all necessary considerations for successful winter legume crops. Eliminating tillage entirely and planting winter legumes directly in standing stubble would assist in snow capture and provide an ideal environment for winter legumes. Even with good agronomic practices, winter hardy germplasm is essential and the development of cultivars with greater winter hardiness is a principal objective of the winter legume breeding program.

The current status of winter pea and lentil breeding efforts, the comparative winter hardiness of existing pea and lentil germplasm, production practices for winter legumes, and control of diseases and insects that affect winter legumes are discussed.

Current Status of Winter Legumes.

Currently, Austrian winter peas are the only winter legume available for production in the U.S. Pacific Northwest; however, winter peas and lentils with edible quality traits are being developed by the breeding program. The current status of the development of winter peas and winter lentils is as follows:

Austrian winter peas. Currently, the production of winter peas in the U.S. is 100 % of the so-called ‘Austrian Winter’ type that includes such varieties as ‘Fenn’, ‘Melrose’, ‘Glacier’ and ‘Granger’. All of these varieties have pigmented vines, flowers and seeds. Because of the pigmentation, these varieties are not normally used as food. By far the most important use of winter peas is for green manuring in the area where the seed crop is produced (northern Idaho) and also in some of the warmer-winter states of southeastern United States. Another major use for the crop is as feed for pigeons. Research is currently underway toward increasing winter hardiness of breeding material and altering the plant habit of improved cultivars toward semi-leafless with the aim of improving standing ability to aid in control of foliar disease and also to improve crop quality. The cultivar Granger, released to the industry in 1995, is a semi-leafless type with long vines but nevertheless very good standing ability.

Non-pigmented winter-hardy peas. Sufficient winter hardiness is available in pea germplasm to permit the development of fall-sown types. For winter peas to be used as edible types, the pigmentation of the flowers, vines and seeds, so characteristic of Austrian Winter peas needs to be eliminated. Varieties with non-pigmented flowers, vines and seeds have reduced tannins, are more palatable as feed, and could also be used as food. The initial white flowered selections that were tested in 1994 and 1995 (Table 2) had sufficient hardiness but were tall and lodged very badly; however, the more recent selections (Table 3) have much improved standing ability. Selection PS9530645 is a semi-leafless "Afila" type with very good standing ability and high yields. The more recent selections also have larger seeds. Additional selections are currently being evaluated for winter hardiness, standing ability, seed size and yield.

Winter hardy lentils. There is exceptional winter hardiness in lentil germplasm that is available for breeding purposes. The level of hardiness in lentil is comparable to that of winter wheat. Breeding lines have been developed in three classes including small red cotyledon, small yellow cotyledon and large yellow cotyledon types (Tables 4 and 5). Comparisons of winter types to the commonly produced spring types have been difficult to make because of the nature of the material. Winter hardy selections have a decumbent and late flowering habit when planted in the spring and mature very late and have low yields. However, when spring types are planted in the fall, they usually do not survive the winter. Consequently, making direct comparisons of the lines is difficult. When the best of the spring types, planted in the spring, are compared to the best of the winter types, planted in the fall, has been an advantage for the winter types. Yields of winter lentils have been 30 to 50% greater than their spring counterparts but in recent years, the lines selected for quality traits have not shown that advantage. This indicates that additional breeding needs to be done on winter lentil to improve both yield and quality.

 

Practices and Considerations for Successful Winter legumes.

Tillage practices that promote snow cover and protection. Producers of winter peas use rough tillage prior to establishment of the crop in the fall. The rough tillage and residues from the previous crop, usually wheat, are essential for capturing snow that insulates the plants and reduces or prevents winter killing. Similar practices would be beneficial to winter lentils.

Fertility. Excessive nitrogen reduces winter survival by promoting vegetative growth and increasing water concentration in the epicotyls, which makes the plants more prone to winter injury (Kephart and Murray, 1989). This finding is in general agreement with the view of Levitt (1980) that indicated that the loss of hardiness was related to changes in plant moisture relationships during cold acclimation. Phosphorus fertilization did not influence winter hardiness in a two-year study (Kephart and Murray, 1989).

Seed Quality and Seed treatments. Good quality seed is required for successful fall planting of winter legumes. The commonly grown Austrian Winter pea is usually treated with a fungicide to prevent seed rotting. Also, the seeds are treated with Molybdenum to overcome soil deficiency in that minor nutrient.

Planting time. Optimum planting time is essential to winter survival. The time of planting must allow for early fall growth and adequate acclimation to cold temperatures of the winter months.

Planting density. Close plant spacing enhances winter survival. The close spacing of winter pea plants improves survival by providing mutual protection from the cold. Also, close plant spacing improves snow capture.

Weed control. Winter plantings of peas and lentils are often plagued by infestations of weeds. Control is not practiced in crops intended for green manuring. However, those crops intended for seed harvest must be treated with herbicides to reduce infestations.

Insect control. Pea leaf weevil (Sitona lineatus) damage can be substantial in winter peas and requires control of the insect. Seed weevil (Bruchus pisorum) can also be a problem but can be controlled with the same chemicals as used on spring-sown peas. There has been no leaf weevil problem for winter lentils.

Diseases. The major diseases of winter pea are Ascochyta blight caused by Phoma medicaginis var. pinodella and Sclerotinia white mold caused by Sclerotinia sclerotiorum. Control of both of these diseases is through crop rotation. The recently released cultivar, Granger, with its’ semi-leafless plant habit is expected to be more tolerant of these diseases by remaining upright longer in the growing season and thereby suppressing disease development. It is anticipated that foliar diseases such as ascochyta blight are a potential problem with winter lentil.

Summary.

Progress is being made in the development of winter hardy peas and lentils that can be planted directly in standing stubble without tillage. The semi-leafless type of pea is expected to provide an escape from foliar disease and improve yields and crop quality. Lentil breeding material has greater winter hardiness when compared winter peas. Currently, several types are under development that should enable fall planting in some areas.

References.

Kephart, K.D. and G.A. Murray. 1989. Nitrogen, Phosphorus and moisture effects on acclimation of winter peas. Can. J. Plant Sci. 69:1119-1128.

Levitt, J. 1980. Responses of plants to environmental stresses. pp. 130-132. In: Vol. 1. Chilling, freezing and high temperature stresses. 2nd ed. Academic press, New York, N.Y.

 

Table 1. Yield (kg ha-1) comparisons of fall and spring sowing of winter type peas (Pullman, 1989).

Cultivar or Selection Spring sown Fall sown Difference
Granger

2236

3507

+1271

Glacier

2648

3240

+ 592

Melrose

2072

3109

+1037

Fenn

1566

2809

+1243

D258-1-3

2240

3788

+1548

D260-1-2

1734

2804

+1070

 

Table 2. Non-pigmented winter pea selections compared to Austrian winter cultivars.

Cultivar or Selection Flower color Yield, 1994 (kg ha-1) Yield, 1995 (kg ha-1)
AW-2

White

2353

3000

AW-22

White

2401

2531

Melrose

Violet

2145

3334

Fenn

Violet

1997

3321

 

Table 3. Preliminary winter pea trial of semi-leafless non-pigmented selections, 1997.

Variety or Selection Plant type 100 seed wt. Yield
PS9530645 Afila --- White 15.9 3168
Glacier Normal 13.4 3161
PS9530550 Normal 15.2 3124
PS9530033 Normal 15.7 3015
Granger Afila 14.9 2890
PS9530726 Afila --- White 15.5 2400

 

Table 4. Large seeded winter lentil trial, 1996-97.

Variety or

Selection

Plant

Height (cm)

100 seed

weight (g)

Seed

yield

LC9440072 42 4.6 1279
LC9440074 37 4.0 1145
LC9440024 41 5.0 982
LC9440046 43 4.8 952
LC9440070 38 5.0 925
LC9440010 44 4.0 901
LC9440005 43 5.2 898
Wa8649041 42 2.5 663
LC9440148 38 4.7 645
LC9440302 37 4.4 528

 

Table 5. Small seeded winter lentil trial, 1996-97.

Variety or

Selection

Plant

Height (cm)

100 seed

wt. (g)

Seed

yield

WA8649090 32 2.9 1658
LC9440176 39 3.8 1145
LC9440035 40 3.8 838
LC9440258 38 3.7 819
LC9440009 33 3.4 809
LC9440284 37 3.3 769