December, 1910.] 



505 



Edible Products. 



At the time of my visit pure strains of 

 these rices were growing side by side in 

 plots 12 x 32 feet, the whole experiment 

 occupying ten acres and constituting 

 model trial grounds. In addition to the 

 extensive experiments just mentioned; 

 there were 1,200 other field experiments of 

 varying size, from those embracing only 

 a lew hybrid plants to plots a rood square, 

 in which the plants were just reaching 

 maturity. A half-dozen men were 

 engaged in taking field notes, 3nd 

 each individual plant was considered 

 separately. 



The systematic arrangement of the 

 experimental plots and the thoroughness 

 with which the work was done was an 

 object lesson deserving attention, and 

 the writer personally got many valuable 

 suggestions. In the breeding work, 

 straight selection, by the " single-ear 

 method," artificial crossing or hybridi- 

 sation, and mutations or sports, are made 

 use of. In the season, which was then 

 closing, fully 10,000 crosses had been 

 made. Of these about 30 per cent, are 

 usually successful. The hybridisation is 

 all done under glass, With the breed- 

 ing project well worked out beforehand, 

 the individual parents are planted in 

 separate plots, and at the proper time 

 hand-pollinated in the green-house. 

 Three to five florets in each panicle are 

 cross-pollinated, and are then covered 

 with paraffin paper bags to prevent 

 possibilities of accidental fertilisation. 



The principles involved in Mendel's 

 theory of heredity and in De Vries' 

 mutation theory are well understood and 

 are extensively applied in their breeding 

 work. In applying Mendel's theory to 

 rice hybrids, a large number of crosses 

 have given results agreeing closely with 

 those which Mendel and other workers 

 in other crops have obtained. The 

 practical application of these theories in 

 breeding work is anticipated with greater 

 assurance than ever, and already a 

 number of valuable crosses have been 

 effected. 



In extensive plantings of pure strains, 

 exceptional opportunity is afforded for 

 the study of mutations, and this phase of 

 research is not being neglected. It is 

 interesting to note that during the 

 season just past the most careful search 

 of the entire fields, in which there were 

 fully half-a-million plants, discovered 

 less than- one hundred mutations and 

 natural hybrids, these variations doubt- 

 lessly including also some " rogues," 

 This indicates two things ; first, that 

 mutations are extremely rare in the lice 

 plant ; and second, that natural crossing 

 is exceptional— a fact confirmed by the 

 writer's experiments some years ago. 

 64 



The publication of this view, however, 

 brought a good deal of criticism from 

 some quarters. 



Whenever a superior new variety is 

 developed, or an old strain improved, 

 seed of it is distributed among the 

 Prefecture Demonstration Stations in the 

 rice-growing sections, first where the 

 plant is grown for at least two seasons. 

 If promising, or at least superior to the 

 rices already grown, the seed is dis- 

 tributed among the farmers for general 

 cultivation. A number of the best 

 varieties now grown in Japan were 

 developed in this way, and their high 

 quality is maintained by Government 

 inspection. The whole system is an 

 admirable one, worthy of adoption in 

 Hawaii. 



II. Insects and Fungus Diseases 

 Affecting Rice. 



Japan has a serious problem in the 

 wide dissemination of the insect pests 

 aud fungus diseases of the rice plant. 



Aside from the outbreak of the army- 

 worm, Heliophila unipuncta last year, 

 Hawaiian rice has been singularly free 

 from insect pests or fungus diseases. For 

 this very reason it seems important to the 

 writer that a warning should be sounded 

 as to the danger there is to our rice in- 

 dustry in the Japanese pests. Since the 

 time that certain imported Japan milled 

 rice was refused landing at Honolulu 

 in 1907, the Rice Export Association of 

 Japan has taken every possible pre- 

 caution to prevent the exportation of 

 infested grain, but far more serious 

 than the grain pests are the insects and 

 fungus diseases which affect the plant. 

 The most serious of these are two lepi- 

 dopterous insects which bore in the 

 stem, Chilo simplex, But!., and Schceno- 

 bius bipuntifer, Walk. The former is 

 double brooded, and many larvae will 

 be found in a stem ; the latter produces 

 three broods a year; and the larvae will 

 be found singly. It would seem that the 

 danger of introducing these pests lies in 

 the importation of rice straw used for 

 packing. Fortunately they are para- 

 sitized in several stages. The most 

 efficient natural enemy is the egg para- 

 site, Trichogramma japonicus, Ashm. 

 Were it not for this and other parasites 

 the losses from the borers alone would 

 be very great ; but even as it is, the 

 writer is informed that in the worst 

 infested regions fully fifty per cent, of 

 the crop is sometimes lost. The borers 

 are also controlled to some extent by 

 burning infested plants when discovered. 

 Such plants are easily distinguished by 

 their pale colour at or near maturity 



