1. Corn breeding in my country began in the early 20th century. In 1900, Luo Zhenyu from the Capital University took the lead in introducing European and American corn varieties and cultivation techniques in books and periodicals. Subsequently, "Journal of Agricultural Sciences" began to publicize improved corn varieties and cultivation knowledge.

Since 1926, Wang Huan of Jinling University and others have isolated inbred lines and assembled hybrids for teaching use. In 1930, Zhao Lianfang and others of Central University began to breed inbred lines. In 1931, Shanxi Province Ming Xian School conducted an introduction test of American corn varieties in Taigu, and selected the Golden Queen variety, which was promoted and planted in North China, Northeast China, Southwest China and other provinces.

2. The introduction of sweet potatoes to China originated in the 21st year of Wanli (1593). During the Ming Dynasty, Chen Zhenlong, a native of Changle, Fujian, who had been doing business in Luzon (the Philippines) for many years, and his son Chen Jinglun, saw a root crop called "sweet potato" growing there. The root was "as big as a fist, with a vermilion skin and a crispy heart." The juice is edible both raw and cooked, the yield is high, and it can be planted widely and tolerate barrenness."

Thinking of the poor land and lack of food in his hometown of Fujian, which has many mountains and few fields, Chen Zhenlong was determined to introduce sweet potatoes to China. In 1593, the Philippines was under Spanish colonial rule. Sweet potatoes were considered a rare commodity and were "not allowed to leave the country." After careful planning, Chen Zhenlong "took potato vines and twisted them into the water-drawing rope" and smeared mud on the rope. In the early summer of 1593, he cleverly avoided the inspection of the colonial checkpoint and "began to cross the sea."

After seven days of sailing, we returned to Xiamen, Fujian Province in late May of the lunar calendar. Because sweet potato comes from outside the region, people in Fujian call it "sweet potato". Chen's introduction of sweet potatoes was discussed in Ming Dynasty scholar Xu Guangqi's "Agricultural Policy Complete Book" and Tan Qian's "Zao Lin Zazu".

Extended information:

1. Morphological characteristics of corn

A tall annual herb. The stalk is upright, usually unbranched, 1-4 meters high, with aerial pillar roots at each node at the base. The leaf sheath has transverse veins; the ligule is membranous, about 2 mm long; the blade is flat and wide, linear-lanceolate, the base is rounded and ear-shaped, hairless or pilose, the midrib is thick, and the edges are slightly rough.

The terminal male panicle is large, and the main axis, the raceme axis and the axils are all covered with fine pubescence; the male spikelets are twin, up to 1 cm long, with one spikelet stalk long and one short, respectively. 1-2 mm and 2-4 mm, puberulent; two glumes nearly equal in length, membranous, with about 10 veins, ciliated; lemma and palea are transparent and membranous, slightly shorter than the glume; anthers orange-yellow; Approximately 5 mm long.

The female inflorescence is enclosed by many broad sheath-like bracts; the female spikelets are twin, arranged in 16-30 longitudinal rows on a strong sequence axis, the two spikelets are equal in length, broad, veinless, with Ciliated; lemma and lemma are transparent and membranous, pistil has extremely long and thin linear style.

The caryopse is spherical or oblate. When mature, the glumes and palea are exposed. Its size varies with different growth conditions. It is generally 5-10 mm long and slightly wider than its length. The embryo length is 1/2-2/3 of caryopsis. Chromosome 2n=20, 40, 80 (Sarma et Sharma, 1986; Molina, 1986). The flowering and fruiting period is in autumn.

2. Morphological characteristics of sweet potato

It is an annual herb with round, oval or spindle-shaped roots in the underground part. The shape, skin color and flesh color of the roots vary depending on the variety or soil. Varies. The stems are lying or rising, occasionally twined, multi-branched, cylindrical or ribbed, green or purple, sparsely pubescent or hairless, and adventitious roots are prone to occur at the stem nodes.

The shape and color of the leaves often vary between different varieties, and sometimes they have different leaf shapes on the same plant. They are usually broadly oval, 4-13 cm long, 3-13 cm wide, entire or 3-5 (-7) lobes, the lobes are broadly ovate, triangular ovate or linear-lanceolate, the base of the leaf is heart-shaped or nearly truncate, the top is acuminate, both sides are sparsely pubescent or nearly hairless. The leaf colors include dark green, yellow-green, purple-green, etc. The color of the top leaves is one of the characteristics of the variety; the petioles vary in length, 2.5-20 cm long, and are sparsely pubescent or hairless.

The cymes are axillary, with 1-3-7 flowers gathered into an umbrella shape. The peduncle is 2-10.5 cm long, slightly stout, hairless or sometimes sparsely pubescent; the bracts are small and draped. Needle-shaped, 2-4 mm long, apex awn tipped or abrupt, falling early; pedicel 2-10 mm long; sepals oblong or oval, unequal length, outer sepals 7-10 mm long, inner sepals 8 mm long -11 mm, the tip suddenly becomes a pointed shape, hairless or sparsely hairy.

Corolla is pink, white, lavender or purple, bell-shaped or funnel-shaped, 3-4 cm long, hairless on the outside; stamens and styles are hidden inside, and the base of the filaments is hairy; ovary 2-4 Roomy, hairy or sometimes hairless.

Baidu Encyclopedia-Corn

Baidu Encyclopedia-Sweet Potato