What a weird thing! Are pears divided into male and female?

Pear trees are widely planted in the world and have a cultivation history of more than 3,000 years in my country. They are the third largest fruit in my country after citrus and apples, and enjoy the reputation of "the king of fruits". Pears are widely distributed in my country. Except for Hainan Province and Hong Kong and Macao, pear trees are commercially cultivated. The cultivated varieties cover five populations: white pear, sand pear, autumn pear, Xinjiang pear and Western pear. As of 2022, there are 85 countries and regions in the world engaged in commercial pear production, of which my country's pear harvesting area and output account for about 70% of the world (FAO data). In 2022, the national pear output will reach 19.265 million tons.

There are many benefits to eating pears. They can replenish water and moisturize the throat, prevent constipation, help lose weight and control weight, and fight inflammation and oxidation. There is a saying among the people that "one pear moisturizes three autumns". The sweet and juicy pears that can be called "natural mineral water" are very suitable for replenishing water and nutrients in autumn.

But how do you pick a good pear? In addition to different varieties, "male pears" and "female pears" are a topic that consumers often talk about when buying pears. Producers and consumers will tell you that when buying pears, you should choose "female pears" instead of "male pears." "Female pears" are juicy, crisp, sweet and delicious; "male pears" have a lot of residue, taste bland, and are not delicious.

So how do you tell the difference between male and female pears? Are female pears really as delicious as people say?

First, let's look at what is a "male pear" and what is a "female pear". There is still no accurate scientific definition of "male pear" and "female pear", and there are not many related research reports. Usually, we use the presence of the calyx after the pear matures as the criterion for distinguishing "male pear" from "female pear". That is, "male pear" refers to the fruit with the calyx remaining, while "female pear" refers to the fruit with the calyx falling off.

Figure 1 Different forms of “male pear” and “female pear”

From this we can see that dividing pears into "male" and "female" is actually incorrect from a botanical point of view, because pears are bisexual flowers and most of them are self-incompatible, that is, most pears cannot complete their own pollination, and other types of varieties need to be configured as pollination trees, so pear fruits are basically "bisexual fruits", and there is no distinction between "male" and "female", so "male pear" and "female pear" are just colloquial names.

Figure 2 Different forms of “male pear” and “female pear”

The sepals of the fruits of the main pear varieties in my country, such as 'Korla Fragrant Pear' and 'Dangshan Pear', often remain at the top, forming what is commonly known as "male pears". The calyx end of the "male pear" fruit is protruding and the shape is irregular, and it is accompanied by problems such as increased stone cell content, reduced sugar content, and diluted flavor. The "female pear" usually has a regular appearance, good-looking, calyx shedding, sunken calyx end, larger fruit, smaller fruit core, good taste, fewer stone cells, and high soluble solids content. Of course, these differences are mainly defined by sensory organs, not scientific and accurate analysis results. In addition, because the sepals at the top of the fruit remain, it provides a more favorable place for pests and diseases to live. Therefore, domestic and foreign consumers have a low acceptance of "male pears".

Is there a way to turn an unwelcome "male pear" into a "female pear"? The answer is yes.

In the process of pear production, some producers increase the number of "mother pears".
Cultivation and management measures are often used to reduce the number of "male pears" that bear fruit. For example, using plant growth regulators (commonly known as calyx-removing agents) during the flowering period can promote calyx removal and increase the number of "female pears". There are also methods of artificial calyx cutting to remove the calyx end for production, such as the common "scar" pears of 'Laiyang Chili Pear'.

Figure 3 Effects of sepal treatment on Laiyang Chili pear fruit at the early stage of fruit development

Figure 4 The process of pinching the flowers of Laiyang Chili pear (picture from the Internet)

To sum up, "male pear" and "female pear" are just common names given to two different forms of pears, and scientists are also constantly contributing scientific and technological strength to increase the number of "female pears".