Pyrus × bretschneideri Rehder - Rosaceae - 白梨 bái lí (chin.), Chinese white pear, ya pear, **Weiße Birne**

Deciduous tree, up to 5–8m tall, native to northern China; fruit creamy-white to yellow, with fine brown dots, ovoid or subglobose. "This species is commonly cultivated in N China, preferring sunny, dry, loamy soils. It includes many important forms with excellent fruit." [[http://www.efloras.org/florataxon.aspx?flora_id=2&taxon_id=200011180]]

"Recent molecular genetic evidence confirms some relationship to the Siberian pear (P. ussuriensis), but it can also be classified as a subspecies of the Chinese pear (P. pyrifolia)." [[http://en.wikipedia.org/wiki/Pyrus_%C3%97_bretschneideri]]

"Volatiles from stored Yali pear (Pyrus bertschneideri Reld) were studied using high-resolution gas chromatography and the solid-phase microextraction (SPME) method of gas chromatography/mass spectrometry (GC/MS). The dominant components were ethyl butanoate, ethyl hexanoate, α-farnesene, hexanal, ethyl acetate, hexyl acetate, ethanol and so on. By using GC-olfactometry, it was demonstrated that the volatile compounds from SPME were responsible for the aroma of Yali pear." \\
[Changes in the volatile compounds and chemical and physical properties of Yali pear (//Pyrus bertschneideri// Reld) during storage. Chen, J. L., Yan, S., Feng, Z., Xiao, L., Hu, X. S., Food chemistry, Vol.97(2), 2006, 248-255]

"The aromatic components of 3 pear cultivars belonging to Pyrus bretschneideri Rehd. and 3 cultivars belonging to P. pyrifolia Nakai were extracted by Head-Space and analyzed by Gas Chromatography-Mass Spectrometric (GC-MS). The results showed that the numbers and contents of main aromatic compounds, contents of main aromatic categories and total aromatic components had some difference among these cultivars. The total aromatic components, the content of aldehydes and its proportion in the total aromatic, components in 3 cultivars of P. bretschneideri were higher significantly than those of other 3 cultivars of P. pyrifolia. The hexanal was the common component and the highest one in these 6 cultivars. Compared with 3 cultivars of P. pyrifolia, the content of hexanal in the 3 cultivars of P. bretschneideri was higher significantly. Hexanal, 1-hexanol and acetic acid and hexyl ester were the characteristic flavor compounds of these 6 cultivars. Both the characteristic flavor compounds and odor units existed some difference in these 6 cultivars. Odor units of hexanal and acetic acid, hexyl ester in 3 cultivars of P. bretschneideri were higher than those of the 3 cultivars of P. pyrifolia significantly." \\
[GC-MS analysis of fruit aromatic components of pear cultivars originated from different species of Pyrus. ChangPing, T., JingLi, W., XiaoJing, L., Na, W., HaiBo, W., JiaZheng, S., XueSen, C., Journal of Fruit Science, Vol.26(3), 2009, 294-299]