Transcript Germplasm
Germplasm 1 ...is both the genetic material (genes, groups of genes, chromosomes) that controls heredity and the tissues, organs, and organisms which express variation Contained in that genetic material Why are genetic resources important ? • Introduction of new plants • Food, fiber, medicinal or ornamental • Changing diets: introduction of the potato • Modification • Plants collected in wild often have limited value per se • We want adaptation to new environments • Changes in size, color number of different tissues • We want those changes to have a genetic basis (heritable) • Germplasm is the raw material for diversity which is the basis for selection (plant breeding) 2 3 Diversity in Brassica • Hundreds of different species • Six (6) species are cultivated • The two most common are: – B. oleracea – B. rapa Centers of Diversity Brassica oleracea rapa 4 B. oleracea • Cabbage - var. capitata - Domesticated from Kale (non-heading) - Cultivated for medicinal purposes - hard headed types developed about 800 AD - Red cabbage described in 1570 in England • Cauliflower - var. botrytis - Evolved from broccoli - 6th century B.C. • Broccoli - var. italica - Domesticated from wild cabbage - Grown by Greeks and Romans, introduced into England 16th century , later introduced into U.S. in early 19th century. 5 6 The part of the plant of greatest interest to man is the part that is modified the most. - J.R. Harlan Brassica oleracea selection results in six different vegetables Kale Leaves Broccoli Flowers and stems Cabbage Terminal bud Brussels sprouts Lateral buds Cauliflower inflorescence Kohrabi Stem 7 Six vegetables 8 Cabbage Kale Brussel sprouts Broccoli Kohlrabi Cauliflower cabbages 9 For fresh market as savoy type is hard to clean Red Savoy Broccoli 10 • Produced in winter in Salinas Valley of California • Production and consumption has tripled since 1970 • The tissue we consume is the young inflorescence and flowering buds. The flower primordia are united into clusters • Buds are functional flowers Cauliflower 11 • Consists of a dense mass of branched floral structures • The edible portion is a thickened fleshy inflorescence • As the inflorescence ages, there is rapid elongation. To produce functional flowers axillary buds are formed 12 B. rapa common members napa Bok-choy Turnip Rab Pak Choy B. rapa var. chinense 13 • White fleshy petioles • minimal vernalization required for bolting • less temperature sensitive than Chinese cabbage, thus, wider adaptation Chinese cabbage B. rapa var. pekinensis 14 Non-heading Chinese cabbage 15 B. rapa var. pekinensis 16 Fast Plant • Dr. Paul Williams - UW r. •Brassica rapa • Flowers in 16 days • Harvest seed in 35 days • Plants are 10-12 cm tall • Can be planted in a plastic soda pop bottle • GERMPLASM • tissues, organs, seeds, genes, groups of genes • any material that carries hereditary information The world's food supply is based on intensive agriculture, which relies on genetic uniformity. But this uniformity increases crop vulnerability to pests and stresses. 17 Scientists need access to genetic diversity to breed varieties that can resist pests, diseases, and environmental stresses. The National Plant Germplasm Service (NPGS) aids the scientists and the need for genetic diversity by: • acquiring crop germplasm • preserving crop germplasm • evaluating crop germplasm • documenting crop germplasm • distributing crop germplasm NPGS is a cooperative effort by public (State and Federal) and private organizations to preserve the genetic diversity of 18 plants. Many important crop species originate outside the United States New germplasm (accessions) enter NPGS through collection, donation by foreign cooperators or international germplasm collections. The germplasm is evaluated, maintained, and made available for distribution. You can order germplasm ! (usually free) http://www.ars-grin.gov/index.html 19 Go to Summary statistics The Controversy: Who owns the germplasm? Who should benefit from research to improve a plant species by breeding and/or genetic engineering? 20