The present invention relates to coated seeds. The coated seed according to the invention is a seed coated with a coating mass composition comprising 70 to 95 parts by weight of a clay mineral of double-chain structure and 30 to 5 parts by weight of a hydrophobic compound. The coated seed provided by the invention has a coating layer of adequate hardness and yet insures good germination characteristics, thus being contributory to the rationalization and development of agricultural production.

A method for substantially improving the bulk flow properties of pesticide-treated plant seeds is disclosed. The seeds are treated with low levels of a polydimethylsiloxane lubricant which is applied either to seeds that have already been treated with a pesticidal substance or to seeds simultaneously with a pesticidal substance. The polydimethylsiloxane lubricant can be applied either by coapplication from separate compositions or by the application of a composition containing both the pesticidal substance and the polydimethylsiloxane lubricant.

The germination of seeds is improved by treating the seeds with a solid-form super absorbent polymer that has absorbed water. Super absorbent polymer particles that contain an amount of water such as about 5 to 7 times their weight that is significantly less than the amount of water they are able to absorb such as about 80-120 times their weight and do not substantially adhere to each other are mixed with seeds to form a mixture that may contain a volume ratio of seeds to polymer particles of 0.2 to 5:1. The mixture is stirred while supplying air or gaseous oxygen into the mixture for a time and at a temperature sufficient to cause the seeds to imbibe sufficient water to enhance their vigor for sprouting, but insufficient to cause sprouting. The mixture is sieved to obtain seeds having essentially no adhering polymer residue of the particles, after which the seeds may be dried. The polymer particles may be spherical, and before absorbing water have a size of 50 to 300 .mu.m. A fine powder of hydrophobic material such as silica, calcium stearate, magnesium stearate or barium stearate may be coated on the polymer particles before or after absorbing water in an amount of 0.1 to 5 weight percent to further prevent adhesion between the particles.

The present invention is characterized by coating a seed with from 0.1 to 25% by weight of a powder (A) composed of one or both of montmorillonite and bentonite and having an average particle diameter of 30 .mu.m or less and from 99.9 to 75% by weight of a powder (B) composed of a material other than montmorillonite and bentonite and having an average particle diameter of at least 10 .mu.m and at most 30 .mu.m using a polyvinyl alcohol aqueous solution having an aqueous solution viscosity at 25.degree. C. of 50 mPa.multidot.s or less as a binder. Consequently, a coated seed obtained by coating a seed, especially a light-favoured seed, easily absorbs water in sowing and is easily cracked in absorbing water. Further, the easy cracking thereof remains unchanged with the course of time. In the coating, formation of by-product seedless spherical pellets is little observed.

A manufactured seed is disclosed which comprises a plant embryo preferably encapsulated, or at least in contact with, a hydrated oxygenated gel. The gel can be oxygenated by passing oxygen gas through a gel solution before curing the gel or by exposing the gel to oxygen gas after curing. The gel is preferably oxygenated by adding to an uncured gel solution a suitably stabilized emulsion of a perfluorocarbon compound or a silicone oil, which compounds are capable of absorbing large amounts of oxygen, and are non-toxic and inert. The seed analog can further comprise an outer shell at least partially surrounding the gel and embryo, thereby forming a capsule. The outer shell preferably is shaped to aid the radical of a germinating embryo in protrusively rupturing the capsule, thereby facilitating successful germination and minimizing incidence of seedling malformation. Other shell materials are selected to provide requisite rigidity to the capsule while imparting minimal restriction to successful germination. In a preferred embodiment for germinating embryos having cotyledon(s), at least the cotyledons are enclosed in a porous material resistant to penetration by the growing cotyledon(s), and the embryo and porous enclosure are encapsulated in a hydrated gel.