Brassica Tournefortii

Ecology of Sahara Mustard, Brassica tournefortii

Jodie S. Holt and Robin G. Marushia University of California, Riverside Cooperators: Matt Brooks and Melissa Trader U.S. Geological Survey Origin and Habitat of B. tournefortii

•Mediterranean region •Grows on sand dunes and alluvial sand •Adapted to drier habitats of Middle East, central and western Asia •Grown as oilseed crop in marginal dry lands in India •Considered for breeding for drought and aphid resistance •No hybridization with other Brassica species Brassica tournefortii in the U.S. Brassicas in California

•5 related species in California— – Brassica juncea, napus, nigra, rapa (=campestris), geniculata (=Hirschfeldia incana) • Brassica nigra –disturbed sites across North America • Hirschfeldia incana –disturbed sites in California, Oregon, Nevada •Only Brassica tournefortii is expanding into the desert (?) Distribution of Brassicas (Jepson)

B. nigra

B. tournefortii H. incana Distribution of Brassicas (Cal Flora)

B. nigra

H. incana

B. tournefortii Biology of Brassica tournefortii

•Winter annual •Basal rosette growth form until flowering •Seed dispersal by tumbling plant or dehiscent fruit (siliques) •Unknown— –Phenology –Germination physiology –Regulation of seed production –Seed longevity in seedbank –Effects on soil chemistry, toxicity B. tournefortii Germination

•Wide temperature range –16-32 oC •Tolerates high salt concentration –Up to 1.58 dS/m •Light or darkness •After 10 wk under water

(Bangle and Powell 2004 Mojave Desert Science Symposium) Brassica spp. Germination

•Light or darkness •Species differences – B. tournefortii -100% germination –No differences between Riverside and Coachella B. tournefortii – B. nigra and H. incana -44 to 76% germination •Temperature responses (day/night oC) –Germ at 19/7 > germ at 23/9 > germ at 27/10 •Moisture responses –Germ at 0 bars > -1 bar > -5 bar B. tournefortii Seed Production

(Trader and Brooks 2004 Mojave Desert Science Symposium) Road Effects on Biomass and Seed Production

(Trader and Brooks 2004 Mojave Desert Science Symposium) Comparative Phenology

•Pot experiments –Riverside, CA and Las Vegas, NV – B. tournefortii (inland and desert), B. nigra, H. incana –Quantify development, growth, life span, fecundity •Field experiment –Mojave Desert site – B. tournefortii and native annuals –Quantify development, growth survival, diversity B. tournefortii Phenology in Pots: Inland vs. Desert Populations

100

90 Bolting 80

70 Flowering B. tournefortii : 60 Inland % of Plants 50 Setting Seed 40

0 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 / / / / / / / / / / / / / / / / / / / 7 4 3 0 7 4 1 7 4 1 8 5 2 9 6 2 9 6 3 / / / / / 1 2 1 1 2 3 1 2 2 1 1 2 1 2 / / 3 / / / / 4 / / / 5 / / / 6 6 / / 2 2 3 3 3 3 4 4 4 5 5 5 6 6

100 90 Pops. not 80 significantly 70 different B. tournefortii : 60 Desert 50 % of Plants 40 30 20 10 0

7 4 /3 0 7 4 1 /7 4 1 8 /5 2 9 6 /2 /9 6 3 /1 /2 3 /1 /1 /2 /3 4 /1 /2 /2 5 /1 /1 /2 6 6 /1 /2 2 2 3 3 3 3 4 4 4 5 5 5 6 6 100

Brassica 90 Bolting 80

Phenology 70 Flowering

60 B. nigra Setting in Pots: % of Plants 50 Seed

B. nigra vs. 20

H. incana 0

7 4 /3 0 7 4 1 /7 4 1 8 /5 2 9 6 /2 /9 6 3 /1 /2 3 /1 /1 /2 /3 4 /1 /2 /2 5 /1 /1 /2 6 6 /1 /2 2 2 3 3 3 3 4 4 4 5 5 5 6 6

100

80 Bolting

70 Flowering 60 H. incana Setting Seed 50 % of Plants 40

7 4 /3 0 7 4 1 /7 4 1 8 /5 2 9 6 /2 /9 6 3 /1 /2 3 /1 /1 /2 /3 4 /1 /2 /2 5 /1 /1 /2 6 6 /1 /2 2 2 3 3 3 3 4 4 4 5 5 5 6 6 Brassica Phenology in Pots: Rate of Cotyledon Loss in Brassica Species

100

80 B. tournefortii: 70 Desert

60 % Without B. tournefortii: Cotyledons 50 Inland 40 B. nigra 30

20 B. geniculata 10

7 4 /3 0 7 4 1 /7 4 1 8 /5 2 /1 /2 3 /1 /1 /2 /3 4 /1 /2 /2 5 /1 2 2 3 3 3 3 4 4 4 5 Brassica Phenology in Pots: Rate of Height Growth in Brassica Species

60 B. tournefortii Desert

50 B.tournefortii Inland

40 B. nigra

Average Height B. geniculata 30 (cm)

7 4 /3 0 7 4 1 /7 4 1 8 /5 2 9 6 /2 /9 6 3 /1 /2 3 /1 /1 /2 /3 4 /1 /2 /2 5 /1 /1 /2 6 6 /1 /2 2 2 3 3 3 3 4 4 4 5 5 5 6 6 Brassica Phenology in Pots: Rate of Leaf Production in Brassica Species

B. tournefortii Desert

20 B.tournefortii Inland

15 B. nigra

Average Leaf # B. geniculata 10

7 4 /3 0 7 4 1 /7 4 1 8 /5 2 9 6 /2 /9 6 3 /1 /2 3 /1 /1 /2 /3 4 /1 /2 /2 5 /1 /1 /2 6 6 /1 /2 2 2 3 3 3 3 4 4 4 5 5 5 6 6 Field Phenology Experiment Phenology of B. tournefortii and Native Species: B. tournefortii

100

Bolting Flowering 80

70 Seed Set Dispersal Brassica 60 tournefortii 50 % of Plants 40

8 /2 /7 2 7 2 7 /4 /9 4 9 4 9 /3 /8 3 8 3 /2 2 2 /1 /1 /2 /2 3 3 /1 /1 /2 /2 4 4 /1 /1 /2 1 2 2 2 2 3 3 3 3 4 4 4 Phenology of B. tournefortii and Native Species: Chaenactisstevioides

100

60 Chaenactis stevioides 50 % of Plants 40

30 Bolting Flowering Seed Set

8 /2 /7 2 7 2 7 /4 /9 4 9 4 9 /3 /8 3 8 3 /2 2 2 /1 /1 /2 /2 3 3 /1 /1 /2 /2 4 4 /1 /1 /2 1 2 2 2 2 3 3 3 3 4 4 4 Phenology of B. tournefortii and Native Species: Cryptanthaangustifolia

100

70 Bolting Flowering Seed Set Cryptantha 60 angustifolia 50 % of Plants 40

8 /2 /7 2 7 2 7 /4 /9 4 9 4 9 /3 /8 3 8 3 /2 2 2 /1 /1 /2 /2 3 3 /1 /1 /2 /2 4 4 /1 /1 /2 1 2 2 2 2 3 3 3 3 4 4 4 Rate of Height Growth in B. tournefortii and Native Species

25 Brassica tournefortii

20 Average Height (cm) Chaenactis stevioides 15

Cryptantha angustifolia 10

8 /4 1 8 5 /4 1 8 5 /1 /8 5 2 /2 2 /1 /1 /2 3 /1 /1 /2 4 4 /1 /2 1 2 2 2 3 3 3 4 4 Conclusions

Photo—Mark Dimmitt, Arizona-Sonora Desert Museum)