Mentor Pollen vs. Inbreeding Depression

Ragged Jack is Brassica napus.

Effects of Cross and Self Fertilisation in the Vegetable Kingdom (1876) pp. 395-396
Charles Darwin
The stigmas on two lately expanded flowers on a variety of cabbage called Ragged Jack, were well covered with pollen from the same plant. After an interval of twenty-three hours pollen from the Early Barnes cabbage growing at a distance was placed on both stigmas, and as the plant was left uncovered pollen from other flowers on the Ragged Jack would certainly have been left by the bees during the next two or three days on the same two stigmas. Under these circumstances, it seemed very unlikely that the pollen of the Barnes cabbage would produce any effect but three out of the fifteen plants raised from the capsules thus produced were plainly mongrelized, and I have no doubt that the twelve other plants were affected, for they grew much more vigorously than the self-fertilized seedlings from the Ragged Jack planted at the same time and under the same conditions.

Babajanyan: Inbreeding Rye (1948)
Rye, as is known, is a strict cross-pollinator; isolation leads to utter sterility, and inbreeding to depression in the progeny. In one of the experiments that we have been conducting at our Institute for the past three years and more, self-fertilizing rye plants in isolators were given the pollen of spring wheat. In a number of cases this led to a heightened grain formation. In 1948 one plant by this method showed 20% of grain development compared with only 1% in the case of pure inbreeding; another plant showed 22% of grain development in the presence of foreign pollen and 0 under pure inbreeding; a third plant showed 24% and 0; other cases showed 33% and 2%, 39% and 0, 48% and 0, and 54% and 0. This is the highest figure we have obtained. Thus, such strict cross-pollinators like rye, which produce no seeds with ordinary inbreeding, produce them under the influence of foreign pollen.
  But this is not the most important, although this in itself is an indication of the diminution of the depression of self-pollination. The important thing is that in plants produced in this way the depression of inbreeding is diminished, and in many cases it disappears in the progeny.

Stepanov, K. I. (1960) A study of self pollinated lines of maize obtained by supplementary pollination with foreign pollen. Trud. 1. nauc. Konf. molod. Ucen. Moldav. (Proc. 1st sci. Conf. jun. Sci. Moldav.) pp. 199-205
The depressive effects of inbreeding in two maize varieties were reduced at Kišinev by adding pollen of Atriplex, Hibiscus, pumpkin, sorghum, African millet, rye, wheat or sunflower to obtain the first-generation inbreds. The inbreds produced in this way acquired morphological stability more quickly than inbred lines from pollination with self pollen only.

Zdanov, L. A. (1963) Supplementary pollination of sunflower with foreign pollen. Genetics for Agriculture pp. 387-98.
Compared with sunflower inbreds produced in the usual way, those pollinated with self pollen + pollen of maize or Ricinus set more seed, were taller and slower in development and had a higher oil content and a higher yield. Maize pollen was more beneficial to some genotypes and Ricinus pollen to others. The effects of pollination with self pollen + foreign pollen for two or more years were additive.

Šimanskij, N. K. (1966) Mentor capacity of foreign pollen in supplementary pollination of sunflower. Problems of breeding, genetics and seed production. 7. pp. 56-58.
The sunflower variety Armavir 3497 obtained by repeated self pollination, supplemented with thistle and pumpkin pollen, formed 8.6-40.6% of normal seeds. In the second and third generations the vegetative period of the plants was found to have been shortened by 3-5 days and oil content raised by 0.6-2.1%. Foreign pollination of sunflower affects the development of progeny characters such as plant height, pollen colour, and shape and size of achenes.

American Journal of Botany 86:261-268. (1999)
The effects of pollen load size and donor diversity on pollen performance, selective abortion, and progeny vigor in Mirabilis jalapa (Nyctaginaceae)
Richard A. Niesenbaum
The influence of pollen competitive environment on pollen performance (pollen germination, stigmatic penetration, and pollen tube growth rate), the maturation or abortion of initiated fruit, seed size, and seedling vigor was explored by manipulating the size and diversity of stigmatic pollen loads on Mirabilis jalapa. All aspects of pollen performance significantly increased with the number of pollen grains on a stigma or pollen tubes in a style, but was not influenced by the diversity of pollen donors. Plants tended to mature single-ovulate fruits that came from flowers where pollen load size and diversity were greatest and aborted those where these were lowest. No plants from seeds resulting from pollinations with a single pollen grain survived, but other fitness measures were mostly determined by maternal plant. The data suggest that pollen performance is influenced by pollen competitive environment, and both the genetic diversity of the pollen load and number of competing pollen tubes are important determinants of seed/fruit abortion.

Botany research. No. 8, Nauka i tehnika, Minsk., 61-66 (1966)
The relation between stimulation and the participation in fertilization of individual components of a pollen mixture
Palilov, A.I.; Loboskaja, L.I.
A secondary pollination of pea plants was carried out at varying time intervals with pollen of different genotypes.

Agrobiologija (Agrobiology). 300 p (1964)
The influence of the quantitative relations between the components of a pollen mixture on the selectivity of fertilization
Tatarincev, A.S.; Kozlov, V.I.
The progeny of the apple Wealthy, pollinated by Pepin Londonskij + Malus niedzwetzkyana, had a higher proportion of M. niedzwetzkyana

Trud. plodoovosc. Inst. Micurin. (Trans. Micurin Fruit Veg. Inst ), 21, 21-26 (1967)
Variation in selectivity of fertilization in relation to the quantitative proportions of the components in a pollen mixture
Tatarincev, A.S.; Koslov, V.I.
Variation in selectivity of fertilization was studied in a number of fruit and vegetable crops, including Malus domestica 'Aport', 'Renet Simirenko', 'Parmen zimnij zolotoj', 'Uelsi', 'Pepin londonskij' and 'Koricnoe', M. niedzwetskayana, the radish varieties Triumf, Moskovskij parovoj and the cabbage varieties Amager and Kamennaja golovka.

NAUK Contributed paper sessions abstracts, Volume 2 (1978)
The change in fertilization selectivity depending [on] quantitative ratio of pollen mixture components
Tatarintsev A. S. I. V. Michurin Institute of Fruits and Vegetables, Michurinsk, USSR.
The facts are established confirming of Poljakov and Mikhailov finding in tobacco. Apple-trees, tomatoes, radishes, cabbages and peas were pollinated by a pollen mixture consisting of 2 components. Significant disproportion between percentage of definite component containing in pollen mixture and quantity of seedlings with characteristics, indicating their origin from fertilization by this component was often observed. In a number of cases while definite component dose was decreased in pollen mixture, the selectivity to this component increased significantly.

Genetika, USSR 24(4): 766-768 (1988)
Selective fertilization in tomato with various quantitative proportions of components in the pollen mixture
Tatarintsev, A.S.
In experiments with the maternal varieties Shtambovyi Zolotistyi with the marker gene for bush habit, and Zheneva with the potato leaf marker, the pollen mixtures applied were respectively Shtambovyi Zolotistyi + Kruglik and Zheneva + Kruglik in the proportions 1 : 1 and 1 : 9 by weight. In the Shtambovyi Zolotistyi pollinations, pollen was applied at the flower bud stage, soon after the flower opened and to aging flowers.