Basic Information - Genetics, Genomics and Breeding of Crop Plants - page 29

in seed production fields, with two parents planted in alternating rows.
Because self- and sib-pollination occurred on the female parent in addition
to the desired cross pollination, hybridization percentages were often less
than 50% and the full yield potential of the hybrids was not realized.
Through hybridization between H. petiolaris and H. annuus and
backcrossing with H. annuus , Leclercq (1969) transferred the H. annuus
genome into H. petiolaris cytoplasm and obtained the first cytoplasmic
male sterile (CMS) plants that became the PET1 (French) CMS cytoplasm
currently used in most all hybrids. In the USA, the first hybrids produced
using CMS and a nuclear fertility restorer pollinator were introduced in
1972 and within five years were grown on about 90% of the production
region. The best hybrids yielded over 20% more than open-pollinated
cultivars available at that time. Much of the currently available germplasm
had its origin in this limited early germplasm, resulting in a crop with an
extremely narrow genetic base. Due to the use of a single male sterile
cytoplasm for worldwide hybrid sunflower production and its
consequence of genetic vulnerability, as shown by the catastrophic
southern corn leaf blight disease caused by Bipolaris maydis race T in the
early 1970s (Tatum 1971), a large portion of the interspecific hybridization
research in sunflower has focused on the identification of additional
unique CMS sources and their fertility restoration genes.
More than 300 maintainer, CMS, and restorer lines have been developed
by the USDA-ARS programs or other public researchers (Miller et al. 1992).
Several of these lines have plant introductions (PI) in their pedigrees and
trace their origins back to cultivars such as Peredovik, “VNIIMK 8931”,
Armavirsky 9345, Voshod, and “Smena” for high yield and high oil content.
The use of a combination of inbred lines has led to the development of
uniform, high yielding, high oil hybrids with resistance to major pathogens
and a high degree of autogamy.
Improved open-pollinated cultivars for non-oilseed or confectionery
production also trace their origins to the USSR. Non-oilseed types known
as “Giant” and “Mammoth Russian” were introduced into North America
during the 19th century, and were grown in gardens for food by the early
Russian immigrants to the USA and Canada. These types served as the
basis for the development of improved cultivars for commercial production.
“Mennonite”, “Mingren”, “Commander”, and “Sundak”, all of which had
relatively good achene size, shape and color suitable for the non-oilseed
markets, were the principal cultivars grown during the 1950s through the
1970s. Non-oilseed hybrids were introduced in the USA in 1974 and
currently account for all confectionery production in the USA. Non-oilseed
production in the USA is currently estimated to be about 20% of the total
sunflower production.