Identification of Clover Seeds Robert Price California Dept. of Food & Agriculture Seed Laboratory

Why Clovers? Commonly grown as forage and cover crops Challenging to the seed analyst [15 spp. in AOSA Rules out of ca. 250] Strawberry Clover, Trifolium fragiferum L. White Clover, Trifolium repens L.

Alsike Clover, Trifolium hybridum L. White Clover, Trifolium repens L.

Goals of the Study To try to distinguish seeds of 3 clover species using quantitative measured characters To see how effectively random sets of the seeds can be distinguished by traditional qualitative characters

Quantitative Characters 1. Seed length (cotyledonary lobe) COTLL 2. Seed length (radicle lobe) RADLL 3. Seed width SEEDW 4. Seed thickness SEEDT 5. Weight of 10 seeds

Seed Measurements COTLL RADLL SEEDW

Measurement Results (SPSS) Differences significant at .001 level

But some dimensions much more similar for Alsike and Strawberry clovers

How similar are observers?

Weights of 10 seeds (g)

50 Seed Separation Exercise 15 White clover, T. repens 10 Strawberry clover, T. fragiferum 8 Alsike clover, T. hybridum 10 Red clover, T. pratense 5 Arrowleaf clover, T. vesiculosum 2 Persian clover, T. resupinatum

Strawberry clover, Trifolium fragiferum L.

Conclusions Most seeds of the 3 clover species will be separated efficiently by standard separation by color pattern, radicle lobe divergence, and general size For unmottled seeds of similar length, it may be helpful to weigh the individual seeds and examine under high magnification (Alsike often more roughened)

Alsike Clover, Trifolium hybridum L.

Acknowledgments Referee Participants Debbie Meyer Riad Baalbaki Referee Committee