WHY NAVEL ORANGES ARE SEEDLESS 



A. D. Shamel, Riverside, Calif. 



THE fruits of ihc Washinerton 

 navel oranj^e variety are seedless. 

 The reason for this condition is 

 that the flowers from which the 

 fruits develop are not pollinated. 



The Washin.i^ton navel orange flowers 

 are i>erfect except that the anthers do 

 not develo]) ])ollen. The aiTangement 

 and the de\-elopment of the flowers of 

 this variety are similar to that of seedy 

 \arieties of oranges with the important 

 exception of the production of pollen. 



The writer has repeatedly pollinated 

 W'lushington navel orange flowers with 

 pollen secureil from the flowers of 

 poll en -bearing citrus varieties as, for 

 example, the \'alencia orange. The 

 \'alencia pollen was simply dusted over 

 the receptive stigmas of the Washington 

 navel orange flowers. Such flowers. 

 with the exception of those accidentalh' 

 destroyed, have invariably developed 

 into navel oranges bearing viable seeds. 



SDMI': si;i;nv uraxgks fouxu 



Occasional! >• a Washington navel 

 orange containing one or more seeds 

 has been foimd in the crops from our 

 l)erfomiance record trees. About ten 

 such fruits have been found in a total 

 of more than twenty-five thousand ex- 

 amined. This condition may be ex- 

 plained on the grounds of the accidental 

 transfer of pollen from neighboring 

 pollen-bearing citrus flowers through 

 Oil' agency of the common honey bee. 

 During the blooming period bees are 

 always extremely active in securing 

 honey from orange blos.soms. They 

 probably accidentally i)ollinate a few 

 i)ollenless flowers of the Washington 

 navel orange located near Valencia or 

 other pollen-bearing citrus varieties. 



In the crops from the Rul)y blood 

 orange ]jerfonnance record trees many 

 fruits are found every year with well- 

 develo{)ed navels. The growers of this 

 variety usually explain the ]jresence of 

 navels in the blood oranges as being 

 .'46 



(iue to cross-pollination with the navel 

 orange variet}-. Such is not the case. 

 The navel blood orange fruits are true 

 hwd variations. They occur as single 

 fruit, branch, or entire tree variations 

 of the Ruby blood variety. Some of 

 the blood navel fruits are seedless, but 

 usually they contain seeds. The flowers, 

 so far as studied, are perfect and the 

 anthers develop an abundance of viable 

 pollen. The lack of pollen in the 

 flowers of the Washington navel orange 

 is further evidence that the navel blood 

 fruits are not in any way the result of 

 cross-pollination. 



A SEEDY STRAI.V 



An interesting strain of the navel 

 orange bearing seedy fruits was dis- 

 covered by the writer near Riverside, 

 California, in 1910. The fruits were 

 ha1)itually fully seeded, usually one 

 seed being found in each section of both 

 the primary and secondary parts of 

 the fruits. The trees and fruits have 

 apparently the same characteristics as 

 those of the Washington navel onmge 

 except that the anthers of the flowers 

 develop viable pollen. The seedy strain 

 na\-el orange flowers also dilTer from 

 those of the seedless navel orange 

 (lowers in that some of the stametis are 

 usually abnormal. Some of them de- 

 \elop a petal-like appearance and an- 

 thers which may or may not contain 

 ])ollen, as can be seen by a close inspec- 

 tion of the accompanying illustration. 

 The seeds in the seed\- strain navel 

 (grange fruits are due to the pollen-bear- 

 ing characteristics of the flowers from 

 which the fruits develop. At the time 

 when the stigmatic surface t)f the 

 ])istils of the seedy navel orange strain 

 flowers becomes in a receptive condi- 

 tion, the filaments grow with astonish- 

 ing rapidity. They thmst tiie an- 

 thers past the stigmas lief ore the petals 

 open. As the anthers brush past the 

 stigmas they burst open and an abun- 



